BACKGROUND:

Several studies have investigated the association of breastfeeding status with offspring mortality in Africa, but most studies were from one center only or had limited statistical power to draw robust conclusions.

METHODS:

Data came from 75 nationally representative cross-sectional Demographic and Health Surveys in 35 countries in sub-Saharan Africa conducted between 2000 and 2016. Our study relied on 217 112 individuals aged 4 days to 23 months for breastfeeding pattern analysis, 161 322 individuals aged 6 to 23 months for breastfeeding history analysis, and 104 427 individuals aged 12 to 23 months for breastfeeding duration analysis.

RESULTS:

Compared with children aged 4 days to 23 months exclusively breastfed in the first 3 days of life, those not breastfed had a high risk of mortality at <2 years of age (odds ratio [OR] = 13.45; 95% confidence interval [CI] = 11.43–15.83). Young children who were predominantly breastfed or partially breastfed had moderately increased risk of mortality at <2 years of age (OR = 1.11, 95% CI = 1.03–1.21 for predominant pattern; OR = 1.12, 95% CI = 0.99–1.27 for partial pattern). Compared with children aged 6 to 23 months who were breastfed within the first 6 months of life, those not breastfed had a high risk of mortality (OR = 5.65; 95% CI = 4.27–7.47). Compared with children aged 12 to 23 months who were breastfed for ≥6 months, those who were breastfed for shorter periods had a higher risk of mortality (OR = 2.78, 95% CI = 1.45–5.32 for duration of <3 months; OR = 5.28, 95% CI = 3.24–8.61 for those who were not breastfed).

CONCLUSIONS:

Our findings support exclusive breastfeeding during the first 6 months of life and continued breastfeeding up to 2 years of age recommended by the World Health Organization for reducing mortality of children <2 years old in sub-Saharan Africa.

What’s Known on This Subject:

Several studies have investigated the association of breastfeeding pattern or history with offspring mortality in Africa, but most studies were from one center only or had limited statistical power to draw robust conclusions.

What This Study Adds:

This large study pooling data from 217 674 individuals from sub-Saharan Africa reveals that exclusive breastfeeding during the first 6 months of life, as well as prolonged breastfeeding, reduces the risk of deaths in children <2 years of age.

Child mortality under the age of 5 years has substantially decreased between 1990 (90.6‰, 12.7 million) and 2015 (42.5‰, 5.9 million).1  However, neonatal mortality (age 0–28 days) is still a major public health problem worldwide (2.7 million in 2015), especially in sub-Saharan African countries2  where adequate health care to manage at-risk births is often unavailable or difficult to access.3 

Breastfeeding has been shown to be a major factor associated with improved survival of infants. The World Health Organization (WHO) recommends exclusive breastfeeding during the first 6 months of life and continued breastfeeding up to 2 years of age.4  It was estimated that scaling up breastfeeding to a near universal level could prevent 823 000 annual deaths in children <2 years of age in 75 high-mortality, low- and middle-income countries (LMICs).5 

Although the prevalence of breastfeeding is high in African countries (>95%), <50% of children <6 months were reported to be fed through exclusive breastfeeding in 2010.5  More specifically, the proportions of exclusive, predominant, partial, and no breastfeeding (defined according to whether infants had been given other milk, fluids, or foods, etc) in the first month of life were respectively 53.9%, 26.7%, 13.4%, and 6.1% in Africa in 2000–2010.6  It is therefore important to assess the effects of pattern, history, and duration of breastfeeding on young child mortality in sub-Saharan African countries. To date, several studies have investigated the association between breastfeeding pattern or history and mortality in children <2 years of age, but findings have been inconsistent in Africa.711  In addition, only a few studies have examined the effect of breastfeeding duration on under-2 mortality.12,13 

Using nationally representative and comparable observations in 217 674 children aged <2 years from 75 surveys from 35 countries in sub-Saharan Africa conducted between 2000 and 2016, we evaluated the associations of breastfeeding pattern, history, and duration with under-2 mortality.

Demographic and Health Surveys (DHS) are nationally representative household sample surveys that use a multistage stratified sampling design to collect health and nutrition data for women of reproductive age (15–49 years), their children (0–59 months), and their households in LMICs. Detailed information on the DHS Program has been described elsewhere.14  The main advantages of the DHS Program include high response rates of the study populations, the national representative sampling frame, high-quality interviewer training, and the standardized questionnaire used for data collection across countries and over time allowing international comparability across populations. DHS data collection procedures were approved by the Inner City Fund international institutional review boards and relevant human subject committees in each country. Oral informed consent was provided by each survey respondent (mothers in our study). We used an anonymous public-use data set. In this study, we included DHS Program data from all countries in sub-Saharan Africa surveyed between 2000 and 2016 to increase the statistical power of analyses, given that mortality in children <2 years of age is a rare event. In Supplemental Figs 2 through 4, we present flow charts of data selection for breastfeeding pattern analysis, breastfeeding history analysis, and breastfeeding duration analysis, respectively. We used data of 217 674 children for breastfeeding pattern analysis, 161 732 children for breastfeeding history analysis, and 104 676 children for breastfeeding duration analysis.

The study population included mothers and their most recent live singleton births in the 2 years preceding the survey. Under-2 mortality (per 1000 live births) was defined as deaths within 24 months after birth. To limit reverse causality on association between breastfeeding pattern in the first 3 days after delivery and <2-year deaths, young children dying in the first 3 days of life were excluded. Infants dying within the first 11 months of life were excluded in the analysis on breastfeeding duration. We grouped under-2 mortality by death time as 4 to 28 days, 1 to 11 months, and 12 to 23 months for breastfeeding pattern analysis.

To assess the breastfeeding pattern, mothers who had a child aged <2 years at the time of survey were asked whether and what they offered to drink or eat to her neonates in the first 3 days after delivery. Breastfeeding pattern was categorized into exclusive, predominant, or partial breastfeeding. Exclusive breastfeeding was defined as feeding only breast milk (from the mother or a wet nurse) and nothing else with the exception of vitamin supplements or medicines. Predominant breastfeeding was defined as feeding of breast milk plus plain water or water-based fluids (sweetened or flavored water, teas, fruit juice, coffee, etc). Partial breastfeeding was defined as feeding breast milk plus animal milk, infant formula, or foods. No breastfeeding was defined as not feeding breast milk either from the mother or a wet nurse. These definitions are consistent with the recommendations from the WHO.15  Breastfeeding history (none versus ever) and duration were reported by the mother, and the duration was categorized into <3, 3 to 5, and ≥6 months.

Covariates for the main analyses included maternal age at birth and education level; paternal age at birth and education level; sex of the child, birth order, and birth mode (cesarean versus vaginal delivery); household wealth quintile (first quintile [poorest] to fifth quintile [richest] within each country) and residence (urban or rural); country; and survey year. Smoking status and occupation of parents, antenatal visits and birth size were not consistently collected in several surveys and these covariates were adjusted only in the sensitivity analyses.

The DHS Program uses a complex survey design for participant selection, and clustering, strata, and sampling weights were provided for each survey across countries. To make each survey unique in the pooled data set, the “survey” variable was considered.16  The recalculated clustering, strata, and sampling weights in consideration of the survey variable were used for calculation of overall under-2 mortality prevalence and in the multivariable logistic regression analyses. Kaplan-Meier survival curves were performed according to breastfeeding pattern. We used multivariable logistic regression analysis to examine the effects of breastfeeding pattern, history, and duration on under-2 mortality with adjustment for the mentioned covariates. Subgroup analyses were performed by categories of <2-year death age (4–28 days, 1–11 months, and 12–23 months). We calculated attributable cases to estimate the numbers of infants who could have been saved if women offered exclusive breastfeeding or along other breastfeeding scenarios. With the relative risk (RR) being estimated by the adjusted odds ratio (OR), the etiologic fraction was first calculated as (RR−1)/RR. The numbers of attributable cases were then calculated by multiplying the etiologic fraction by the deaths in the specific exposure groups.

Several sensitivity analyses were performed to test the robustness of our findings. First, other covariates, including smoking status and occupation of parents, antenatal visits, and birth size, were further adjusted separately and simultaneously. Second, the gross domestic product per capita on purchasing power parity (PPP) (current international dollar) at country level in the survey year was further adjusted.

All statistical analyses were performed by using SAS 9.4 (SAS Institute, Inc, Cary, NC). A P value <.05 was considered statistically significant.

Data on breastfeeding pattern in the first 3 days of life and under-2 mortality (4 days–23 months) were available from 75 DHS surveys in 35 countries in sub-Saharan Africa between 2000 and 2016. The total sample size was 217 112 children, ranging from 574 (0.3%) in Swaziland to 22 649 (10.4%) in Nigeria (Supplemental Table 5). The weighted prevalence of under-2 mortality (4 days–23 months) was 32.1‰, ranging between 11.9‰ in Angola and 45.7‰ in Swaziland. Overall, the weighted proportions of exclusive, predominant, partial, and no breastfeeding were 59.8%, 31.0%, 8.3%, and 0.9%, respectively (Supplemental Table 6). The characteristics of mothers, fathers, offspring, and households in the pooled data set by breastfeeding pattern are presented in Table 1.

TABLE 1

Characteristics of the Study Population for Breastfeeding Pattern Analysis

VariablesBreastfeeding Pattern (in the First 3 Days of Life), n (%)P
Exclusive (n = 137 529)Predominant (n = 61 242)Partial (n = 16 140)None (n = 2201)
Maternal      
 Age, y      
  <20 14 764 (58.3) 7964 (31.5) 2316 (9.2) 265 (1.0) <.001 
  20–29 74 186 (64.3) 31 849 (27.6) 8235 (7.1) 1132 (1.0) — 
  30–39 41 306 (63.9) 18 075 (27.9) 4623 (7.1) 677 (1.0) — 
  ≥40 7273 (62.1) 3354 (28.6) 966 (8.2) 127 (1.1) — 
 Education level      
  Illiteracy 55 384 (53.9) 35 417 (34.5) 10 942 (10.7) 968 (0.9) <.001 
  Primary 52 916 (72.1) 16 927 (23.1) 2923 (4.0) 591 (0.8) — 
  Secondary or higher 29 229 (71.2) 8898 (21.7) 2275 (5.5) 642 (1.6) — 
 Marital status      
  Married or living with partner 137 529 (63.3) 61 242 (28.2) 16 140 (7.4) 2201 (1.0) — 
  Single, divorced, or widowed 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) — 
Paternal      
 Age, y      
  <20 1069 (63.3) 462 (27.4) 116 (6.9) 41 (2.4) <.001 
  20–29 41 775 (67.8) 15 269 (24.8) 3906 (6.3) 623 (1.0) — 
  30–39 55 144 (64.4) 23 533 (27.5) 6091 (7.1) 834 (1.0) — 
  ≥40 39 541 (57.9) 21 978 (32.2) 6027 (8.8) 703 (1.0) — 
 Education level      
  Illiteracy 44 849 (51.5) 31 205 (35.8) 10 171 (11.7) 874 (1.0) <.001 
  Primary 48 428 (71.9) 15 595 (23.2) 2799 (4.2) 529 (0.8) — 
  Secondary or higher 44 252 (70.6) 14 442 (23.0) 3170 (5.1) 798 (1.3) — 
Child      
 Sex      
  Male 69 035 (63.0) 31 176 (28.4) 8253 (7.5) 1143 (1.0) .004 
  Female 68 494 (63.7) 30 066 (28.0) 7887 (7.3) 1058 (1.0) — 
 Birth order      
  First 24 241 (62.7) 10 675 (27.6) 3234 (8.4) 486 (1.3) <.001 
  Second 26 930 (66.4) 10 511 (25.9) 2646 (6.5) 444 (1.1) — 
  Third 23 132 (65.7) 9360 (26.6) 2342 (6.7) 350 (1.0) — 
  Fourth 18 780 (64.6) 7962 (27.4) 2019 (6.9) 291 (1.0) — 
  ≥Fifth 44 446 (60.3) 22 734 (30.8) 5899 (8.0) 630 (0.9) — 
Household      
 Wealth quintile, within country      
  First, poorest 32 044 (60.0) 15 571 (29.2) 5250 (9.8) 514 (1.0) <.001 
  Second 29 673 (62.3) 14 014 (29.4) 3548 (7.4) 419 (0.9) — 
  Third 28 345 (64.6) 12 435 (28.3) 2702 (6.2) 421 (1.0) — 
  Fourth 25 399 (65.5) 10 705 (27.6) 2304 (5.9) 384 (1.0) — 
  Fifth, richest 22 068 (66.1) 8517 (25.5) 2336 (7.0) 463 (1.4) — 
 Residence      
  Urban 38 636 (66.3) 15 165 (26.0) 3544 (6.1) 897 (1.5) <.001 
  Rural 98 893 (62.2) 46 077 (29.0) 12 596 (7.9) 1304 (0.8) — 
 Survey year      
  2000–2009 57 673 (58.6) 31 388 (31.9) 8514 (8.7) 792 (0.8) <.001 
  2010–2016 79 856 (67.2) 29 854 (25.1) 7626 (6.4) 1409 (1.2) — 
VariablesBreastfeeding Pattern (in the First 3 Days of Life), n (%)P
Exclusive (n = 137 529)Predominant (n = 61 242)Partial (n = 16 140)None (n = 2201)
Maternal      
 Age, y      
  <20 14 764 (58.3) 7964 (31.5) 2316 (9.2) 265 (1.0) <.001 
  20–29 74 186 (64.3) 31 849 (27.6) 8235 (7.1) 1132 (1.0) — 
  30–39 41 306 (63.9) 18 075 (27.9) 4623 (7.1) 677 (1.0) — 
  ≥40 7273 (62.1) 3354 (28.6) 966 (8.2) 127 (1.1) — 
 Education level      
  Illiteracy 55 384 (53.9) 35 417 (34.5) 10 942 (10.7) 968 (0.9) <.001 
  Primary 52 916 (72.1) 16 927 (23.1) 2923 (4.0) 591 (0.8) — 
  Secondary or higher 29 229 (71.2) 8898 (21.7) 2275 (5.5) 642 (1.6) — 
 Marital status      
  Married or living with partner 137 529 (63.3) 61 242 (28.2) 16 140 (7.4) 2201 (1.0) — 
  Single, divorced, or widowed 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) — 
Paternal      
 Age, y      
  <20 1069 (63.3) 462 (27.4) 116 (6.9) 41 (2.4) <.001 
  20–29 41 775 (67.8) 15 269 (24.8) 3906 (6.3) 623 (1.0) — 
  30–39 55 144 (64.4) 23 533 (27.5) 6091 (7.1) 834 (1.0) — 
  ≥40 39 541 (57.9) 21 978 (32.2) 6027 (8.8) 703 (1.0) — 
 Education level      
  Illiteracy 44 849 (51.5) 31 205 (35.8) 10 171 (11.7) 874 (1.0) <.001 
  Primary 48 428 (71.9) 15 595 (23.2) 2799 (4.2) 529 (0.8) — 
  Secondary or higher 44 252 (70.6) 14 442 (23.0) 3170 (5.1) 798 (1.3) — 
Child      
 Sex      
  Male 69 035 (63.0) 31 176 (28.4) 8253 (7.5) 1143 (1.0) .004 
  Female 68 494 (63.7) 30 066 (28.0) 7887 (7.3) 1058 (1.0) — 
 Birth order      
  First 24 241 (62.7) 10 675 (27.6) 3234 (8.4) 486 (1.3) <.001 
  Second 26 930 (66.4) 10 511 (25.9) 2646 (6.5) 444 (1.1) — 
  Third 23 132 (65.7) 9360 (26.6) 2342 (6.7) 350 (1.0) — 
  Fourth 18 780 (64.6) 7962 (27.4) 2019 (6.9) 291 (1.0) — 
  ≥Fifth 44 446 (60.3) 22 734 (30.8) 5899 (8.0) 630 (0.9) — 
Household      
 Wealth quintile, within country      
  First, poorest 32 044 (60.0) 15 571 (29.2) 5250 (9.8) 514 (1.0) <.001 
  Second 29 673 (62.3) 14 014 (29.4) 3548 (7.4) 419 (0.9) — 
  Third 28 345 (64.6) 12 435 (28.3) 2702 (6.2) 421 (1.0) — 
  Fourth 25 399 (65.5) 10 705 (27.6) 2304 (5.9) 384 (1.0) — 
  Fifth, richest 22 068 (66.1) 8517 (25.5) 2336 (7.0) 463 (1.4) — 
 Residence      
  Urban 38 636 (66.3) 15 165 (26.0) 3544 (6.1) 897 (1.5) <.001 
  Rural 98 893 (62.2) 46 077 (29.0) 12 596 (7.9) 1304 (0.8) — 
 Survey year      
  2000–2009 57 673 (58.6) 31 388 (31.9) 8514 (8.7) 792 (0.8) <.001 
  2010–2016 79 856 (67.2) 29 854 (25.1) 7626 (6.4) 1409 (1.2) — 

—, not applicable.

In the pooled analysis, compared with children aged 4 days to 23 months exclusively breastfed in the first 3 days of life, those who were not breastfed, predominantly breastfed, and partially breastfed were more likely to die during the first 2 years of life (Fig 1). In multivariable logistic regression analysis, adjusted for potential covariates, compared with children aged 4 days to 23 months exclusively breastfed, those who were not breastfed had a higher risk of mortality during the first 2 years of life (OR = 13.45; 95% confidence interval [CI] = 11.43–15.83) and in each of the examined periods (OR = 23.97, 95% CI = 18.94–30.34 in the 4–28-day period; OR = 9.52, 95% CI = 7.68–11.79 in the 1–11-month period; OR = 8.19, 95% CI = 5.13–13.09 in the 12–23-month period) suggesting that the association was still high but attenuated over time (Table 2). In addition, children aged 4 days to 23 months predominantly breastfed or partially breastfed were also at increased risk of mortality before the age of 2 years compared with children exclusively breastfed (OR = 1.11, 95% CI = 1.03–1.21 for predominant pattern; OR = 1.12, 95% CI = 0.99–1.27 for partial pattern). However, a statistically significant association was observed only in the age subgroup of 1 to 11 months in the analysis by age subgroup (Table 2).

FIGURE 1

Kaplan-Meier survival curves of breastfeeding pattern and offspring mortality during age 4 days to 23 months.

FIGURE 1

Kaplan-Meier survival curves of breastfeeding pattern and offspring mortality during age 4 days to 23 months.

Close modal
TABLE 2

Breastfeeding Pattern and Under-2 Mortality (4 Days to 23 Months)

Mortality for Breastfeeding Pattern in the First 3 Days of LifeSample Size, nNo. DeathsOR (95% CI)PAttributable Cases
Mortality: 4 d to 23 mo (N = 217 112)      
 Exclusive 137 529 3643 1 (Reference)   
 Predominant 61 242 2056 1.11 (1.03–1.21) .010 204 
 Partial 16 140 565 1.12 (0.99–1.27) .065 61 
 None 2201 450 13.45 (11.43–15.83) <.001 417 
Mortality: 4–28 d (N = 217 112)      
 Exclusive 137 529 758 1 (Reference)   
 Predominant 61 242 466 1.15 (0.96–1.37) .136 61 
 Partial 16 140 120 0.92 (0.71–1.19) .522 — 
 None 2201 192 23.97 (18.94–30.34) <.001 184 
Mortality: 1–11 mo (n = 215 576)      
 Exclusive 136 771 2352 1 (Reference)   
 Predominant 60 776 1252 1.13 (1.02–1.25) .017 144 
 Partial 16 020 358 1.28 (1.10–1.49) .002 78 
 None 2009 219 9.52 (7.68–11.79) <.001 196 
Mortality: 12–23 mo (n = 211 395)      
 Exclusive 134 419 533 1 (Reference)   
 Predominant 59 524 338 1.02 (0.82–1.26) .869 
 Partial 15 662 87 0.92 (0.67–1.25) .583 — 
 None 1790 39 8.19 (5.13–13.09) <.001 34 
Mortality for Breastfeeding Pattern in the First 3 Days of LifeSample Size, nNo. DeathsOR (95% CI)PAttributable Cases
Mortality: 4 d to 23 mo (N = 217 112)      
 Exclusive 137 529 3643 1 (Reference)   
 Predominant 61 242 2056 1.11 (1.03–1.21) .010 204 
 Partial 16 140 565 1.12 (0.99–1.27) .065 61 
 None 2201 450 13.45 (11.43–15.83) <.001 417 
Mortality: 4–28 d (N = 217 112)      
 Exclusive 137 529 758 1 (Reference)   
 Predominant 61 242 466 1.15 (0.96–1.37) .136 61 
 Partial 16 140 120 0.92 (0.71–1.19) .522 — 
 None 2201 192 23.97 (18.94–30.34) <.001 184 
Mortality: 1–11 mo (n = 215 576)      
 Exclusive 136 771 2352 1 (Reference)   
 Predominant 60 776 1252 1.13 (1.02–1.25) .017 144 
 Partial 16 020 358 1.28 (1.10–1.49) .002 78 
 None 2009 219 9.52 (7.68–11.79) <.001 196 
Mortality: 12–23 mo (n = 211 395)      
 Exclusive 134 419 533 1 (Reference)   
 Predominant 59 524 338 1.02 (0.82–1.26) .869 
 Partial 15 662 87 0.92 (0.67–1.25) .583 — 
 None 1790 39 8.19 (5.13–13.09) <.001 34 

Adjusted for maternal age and education level; paternal age and education level; child’s sex, birth order, and birth mode; household wealth status and residence (urban or rural); country; and survey year. —, such values cannot be calculated because the OR should be >1.

Because the association of predominant and partial breastfeeding patterns on under-2 mortality was larger in the 1- to 11-month age category as compared to the other 2 periods, we performed sensitivity analyses restricted to this period, which revealed consistent results (Supplemental Table 7).

For the association of breastfeeding history (in the first 6 months of life) with under-2 mortality (6–23 months), the total sample size was 161 322 children, ranging from 440 (0.3%) in Swaziland to 16 668 (10.3%) in Nigeria (Supplemental Table 5). The weighted under-2 mortality prevalence (6–23 months) was 18.0‰, ranging from 3.0‰ in Comoros to 25.7‰ in Swaziland. Overall, the proportion of ever breastfeeding was 99.0%. The characteristics of mothers, fathers, offspring, and households in the pooled data set by breastfeeding history categories are presented in Supplemental Table 8.

In the pooled analysis (Table 3), after adjustment for potential covariates, compared with children aged 6 to 23 months ever breastfed within the first 6 months of life, those who were not breastfed had increased risk of mortality before the age of 2 years (OR = 5.65; 95% CI = 4.27–7.47). Subgroup analysis by death time revealed that the association was consistently significant in the 6- to 11-month period (OR = 5.07; 95% CI = 3.66–7.04) and in the 12- to 23-month period (OR = 6.38; 95% CI = 3.94–10.32). Other sensitivity analyses considering other covariates revealed similar findings (Supplemental Table 9).

TABLE 3

Breastfeeding History and Mortality During Age of 6 to 23 Months

Age at DeathHistory of Breastfeeding at 0–5 MonthsSample Size, nNo. DeathsOR (95% CI)PAttributable Cases
6–23 mo (n = 161 322)       
 Ever 159 673 2632 1 (Reference)   
 None 1649 100 5.65 (4.27–7.47) <.001 82 
6–11 mo (n = 161 322)       
 Ever 159 673 1721 1 (Reference)   
 None 1649 65 5.07 (3.66–7.04) <.001 52 
12–23 mo (n = 159 536)       
 Ever 157 952 911 1 (Reference)   
 None 1584 35 6.38 (3.94–10.32) <.001 30 
Age at DeathHistory of Breastfeeding at 0–5 MonthsSample Size, nNo. DeathsOR (95% CI)PAttributable Cases
6–23 mo (n = 161 322)       
 Ever 159 673 2632 1 (Reference)   
 None 1649 100 5.65 (4.27–7.47) <.001 82 
6–11 mo (n = 161 322)       
 Ever 159 673 1721 1 (Reference)   
 None 1649 65 5.07 (3.66–7.04) <.001 52 
12–23 mo (n = 159 536)       
 Ever 157 952 911 1 (Reference)   
 None 1584 35 6.38 (3.94–10.32) <.001 30 

Adjusted for maternal age and education level; paternal age and education level; child’s sex, birth order, and birth mode; household wealth status and residence (urban or rural); country; and survey year.

For the association of breastfeeding duration with mortality during the second year of life (12–23 months), the total sample size was 104 427 children, ranging from 292 (0.3%) in Sao Tome and Principe to 10 656 (10.2%) in Nigeria (Supplemental Table 5). The weighted prevalence of mortality during the second year of life (12–23 months) was 10.6‰, ranging between 0.0‰ in Sao Tome and Principe and 15.9‰ in Niger. Overall, the proportions of no breastfeeding and breastfeeding duration of <3, 3 to 5, and ≥6 months were 1.1%, 0.7%, 0.6%, and 97.6%, respectively. The characteristics of mothers, fathers, offspring, and households in the pooled data set by breastfeeding duration are presented in Supplemental Table 10.

In the pooled analysis (Table 4), after adjustment for potential covariates, compared with children aged 12 to 23 months breastfed for ≥6 months, those who were breastfed for shorter periods were at increased risk of mortality during the second year of life (OR = 2.78, 95% CI = 1.45–5.32 for duration of <3 months; OR = 5.28, 95% CI = 3.24–8.61 for those who were not breastfed). Sensitivity analyses considering other covariates revealed similar findings (Supplemental Table 11).

TABLE 4

Breastfeeding Duration and Mortality During 12 to 23 Months

Breastfeeding Duration (n = 104 427)Sample Size, nNo. DeathsOR (95% CI)PAttributable Casesa
≥6 mo 101 953 913 1 (Reference)   
3–5 mo 589 — — — 
<3 mo 690 16 2.78 (1.45–5.32) .002 10 
None 1195 34 5.28 (3.24–8.61) <.001 28 
Breastfeeding Duration (n = 104 427)Sample Size, nNo. DeathsOR (95% CI)PAttributable Casesa
≥6 mo 101 953 913 1 (Reference)   
3–5 mo 589 — — — 
<3 mo 690 16 2.78 (1.45–5.32) .002 10 
None 1195 34 5.28 (3.24–8.61) <.001 28 

Adjusted for maternal age and education level; paternal age and education level; child’s sex, birth order, and birth mode; household wealth status and residence (urban or rural); country; and survey year. —, such values cannot be calculated because of the limited number of deaths.

Using population-based data (N = 217 112 children) in 35 countries in sub-Saharan Africa, we found that (1) compared to exclusive breastfeeding, suboptimal breastfeeding (predominant or partial pattern) and no breastfeeding significantly increased the risk of mortality of young children aged <2 years; (2) ever breastfeeding decreased under-2 mortality of children aged 6 to 23 months when compared to no breastfeeding; and (3) there was a dose-response association between breastfeeding duration and risk of mortality during the second year of life (age 12–23 months). These findings are consistent with the WHO recommendations for exclusive breastfeeding in the first 6 months of life and continued breastfeeding up to the age of 2 years.

Authors of several studies have assessed the association between breastfeeding pattern and offspring mortality in some countries in Africa, but most studies came from only one center or had limited statistical power to provide robust finding, given that under-2 mortality is a fairly infrequent outcome.711  To our knowledge, there are no related data that are focused entirely on Africa. One previous study including 1677 infants who were followed from birth to 12 months of age from Bangladesh revealed that exclusive breastfeeding in the first few months of life was associated with all-cause mortality as compared to partial or no breastfeeding (OR = 2.23; 95% CI = 1.45–3.44) and, in particular, increased mortality due to respiratory infections (OR = 2.40; 95% CI = 1.14–5.04) and diarrhea (OR = 3.94; 95% CI = 1.47–10.57). This study also revealed that predominant breastfeeding was not associated with under-2 mortality (all P > .05).9  Similarly, another study including 9424 infants who were enrolled at the age of 18 to 42 days from Ghana, India, and Peru revealed the increased mortality between the ages of 6 weeks and 6 months associated with partial breastfeeding (hazard ratio [HR] = 2.46; 95% CI = 1.44–4.18) or no breastfeeding (HR = 10.5; 95% CI = 5.0–22.0) versus exclusively breastfeeding (HR = 1.46; 95% CI = 0.75–2.86) when compared to predominantly breastfeeding.7  In contrast, 1 subsequent meta-analysis including only 3 studies (N = 22 048 children) revealed that compared to exclusive breastfeeding, no breastfeeding was associated with the highest risk of mortality in offspring aged 0 to 5 months (OR = 14.40; 95% CI = 6.13–33.90), followed by partial breastfeeding pattern (OR = 2.84; 95% CI = 1.63–4.97) and predominant breastfeeding pattern (OR = 1.48; 95% CI = 1.13–1.92).17  Estimates from this meta-analysis were consistent with results from a recent large prospective study including 99 938 young children.11  The results of our study with a large sample size (N = 217 674 children) are consistent with this previous meta-analysis. However, these previous other studies were only focused on deaths within the first 6 months of life, whereas our study reveals that partial or predominant breastfeeding pattern also increases risk of death during the period of 1 to 11 months.

Several previous studies have examined the association between breastfeeding history (none versus ever) and risk of under-2 mortality,1823  but the statistical power was generally insufficient, and control for confounders was limited in most of these studies. One previous meta-analysis revealed that compared with children ever breastfed within 6 months, those not breastfed were at increased risk of death (OR = 1.76, 95% CI = 1.28–2.41 among infants aged 6–11 months; OR = 1.97, 95% CI = 1.45–2.67 among young children aged 12–23 months),17  which is consistent with our findings among 161 732 African young children. However, the magnitude of our estimated associations was larger (OR = 5.07, 95% CI = 3.66–7.04 for infants aged 6–11 months; OR = 6.38, 95% CI = 3.94–10.32 for young children aged 12–23 months) than those of that meta-analysis.

To our knowledge, few studies have evaluated the effect of breastfeeding duration on infant mortality. Data from one US study of ∼6000 postneonates (28 days–1 year of age) revealed that longer breastfeeding was associated with lower risk of mortality, with an OR (95% CI) of 0.62 (0.46–0.82) for 3 months or more of breastfeeding.12  Data from the US National Health and Nutrition Examination Survey III of 2277 children aged 6 to 23 months revealed that prolonged breastfeeding decreased the risk of respiratory tract infections, including pneumonia,13  which is an important risk factor for under-2 mortality. Our study also supports the notion that prolonged breastfeeding is associated with reduced under-2 mortality, at least in sub-Saharan Africa.

Our findings emphasize that policy makers, health workers, and mothers in sub-Saharan Africa (and likely in all countries) should promote exclusive breastfeeding during the first 6 months of life and prolonged exclusive or partial breastfeeding up to the age of 2 years. In view of the magnitude of the association between breastfeeding and under-2 mortality, adequate breastfeeding holds the perspective to reduce substantially the currently high under-2 mortality in LMICs. Mechanisms through which breastfeeding is beneficial have been widely described,2426  including exclusive breastfeeding necessarily decreasing exposure to unsafe water and fecal contaminants, which may be associated with the risk of infant mortality due to infectious disease.

Our study has several strengths. First, to our knowledge, our study has the largest study sample (N = 217 112) for assessing the associations of breastfeeding pattern, history, and duration on under-2 mortality, allowing sufficient statistical power to draw solid conclusions. Second, the use of national representative and comparable samples made our findings generalizable to populations in sub-Saharan Africa and, likely, in other LMICs. Third, we adjusted our analyses for several potential confounders and performed several sensitivity analyses, which makes our findings robust. However, several limitations should also be noted. First, there might be reverse causality between breastfeeding pattern and duration and under-2 mortality. Infants who have severe illnesses may not be adequately breastfed or weaned in early life. This is why we excluded infants who died in the first 3 days of life when assessing the association of breastfeeding pattern on under-2 mortality. In addition, infants who died within the first 12 months of life were excluded when assessing the effect of breastfeeding duration on mortality at the age of 12 to 23 months. These attempts have likely significantly reduced the possibility of a bias due to reverse causality. Second, information on breastfeeding pattern, history, and duration was reported by the mother, and recall biases might underestimate or overestimate the strength of our observed associations. Third, although several potential confounders were adjusted for in our analyses, residual confounding may not be fully ruled out. Fourth, meta-regression analysis can be better than pooling diverse data. We did perform a regression analysis in the data from each country, but we cannot calculate reliable ORs because the under-2 mortality is a rare event in the population and the statistical power of analyses from most country studies is too low.

Our results reveal that exclusive breastfeeding during the first 6 months, as well as prolonged breastfeeding up to the age of 2 years, was associated with substantially decreased risk of under-2 mortality. Of note, 682 (22%) children’s lives could have been saved if all mothers had breastfed their infants for 6 months. These findings support the promotion of exclusive breastfeeding up to the age of 6 months and prolonged breastfeeding up to the age of 2 years as an important mean to reduce the burden of under-2 mortality in LMICs, where such mortality is still much higher than in other regions.

We thank the DHS Program for sharing the available data.

Prof Xi conceptualized and designed the study and reviewed and revised the manuscript; Dr Zhao drafted the initial manuscript and reviewed and revised the manuscript; Dr Wu designed the data collation, conducted the initial analyses, and reviewed and revised the manuscript; Drs Bovet, Liang, and Liu critically reviewed the manuscript for important intellectual content; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

FUNDING: No external funding.

     
  • CI

    confidence interval

  •  
  • DHS

    Demographic and Health Surveys

  •  
  • HR

    hazard ratio

  •  
  • LMIC

    low- and middle-income country

  •  
  • OR

    odds ratio

  •  
  • PPP

    purchasing power parity

  •  
  • RR

    relative risk

  •  
  • WHO

    World Health Organization

1
You
D
,
Hug
L
,
Ejdemyr
S
, et al;
United Nations Inter-agency Group for Child Mortality Estimation (UN IGME)
.
Global, regional, and national levels and trends in under-5 mortality between 1990 and 2015, with scenario-based projections to 2030: a systematic analysis by the UN Inter-agency Group for Child Mortality Estimation
.
Lancet
.
2015
;
386
(
10010
):
2275
2286
2
Lawn
JE
,
Cousens
S
,
Zupan
J
;
Lancet Neonatal Survival Steering Team
.
4 million neonatal deaths: when? Where? Why?
Lancet
.
2005
;
365
(
9462
):
891
900
3
Cresswell
JA
,
Campbell
OMR
,
De Silva
MJ
,
Filippi
V
.
Effect of maternal obesity on neonatal death in sub-Saharan Africa: multivariable analysis of 27 national datasets
.
Lancet
.
2012
;
380
(
9850
):
1325
1330
4
World Health Organization
.
Infant and Young Child Feeding. Model Chapter for Textbooks for Medical Students and Allied Health Professionals
.
Geneva, Switzerland
:
World Health Organization
;
2009
5
Victora
CG
,
Bahl
R
,
Barros
AJD
, et al;
Lancet Breastfeeding Series Group
.
Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect
.
Lancet
.
2016
;
387
(
10017
):
475
490
6
Black
RE
,
Victora
CG
,
Walker
SP
, et al;
Maternal and Child Nutrition Study Group
.
Maternal and child undernutrition and overweight in low-income and middle-income countries
.
Lancet
.
2013
;
382
(
9890
):
427
451
7
Bahl
R
,
Frost
C
,
Kirkwood
BR
, et al
.
Infant feeding patterns and risks of death and hospitalization in the first half of infancy: multicentre cohort study
.
Bull World Health Organ
.
2005
;
83
(
6
):
418
426
8
Edmond
KM
,
Zandoh
C
,
Quigley
MA
,
Amenga-Etego
S
,
Owusu-Agyei
S
,
Kirkwood
BR
.
Delayed breastfeeding initiation increases risk of neonatal mortality
.
Pediatrics
.
2006
;
117
(
3
).
9
Arifeen
S
,
Black
RE
,
Antelman
G
,
Baqui
A
,
Caulfield
L
,
Becker
S
.
Exclusive breastfeeding reduces acute respiratory infection and diarrhea deaths among infants in Dhaka slums
.
Pediatrics
.
2001
;
108
(
4
).
10
Edmond
KM
,
Kirkwood
BR
,
Amenga-Etego
S
,
Owusu-Agyei
S
,
Hurt
LS
.
Effect of early infant feeding practices on infection-specific neonatal mortality: an investigation of the causal links with observational data from rural Ghana
.
Am J Clin Nutr
.
2007
;
86
(
4
):
1126
1131
11
NEOVITA Study Group
.
Timing of initiation, patterns of breastfeeding, and infant survival: prospective analysis of pooled data from three randomised trials
.
Lancet Glob Health
.
2016
;
4
(
4
):
e266
e275
12
Chen
A
,
Rogan
WJ
.
Breastfeeding and the risk of postneonatal death in the United States
.
Pediatrics
.
2004
;
113
(
5
).
13
Chantry
CJ
,
Howard
CR
,
Auinger
P
.
Full breastfeeding duration and associated decrease in respiratory tract infection in US children
.
Pediatrics
.
2006
;
117
(
2
):
425
432
14
Corsi
DJ
,
Neuman
M
,
Finlay
JE
,
Subramanian
SV
.
Demographic and Health Surveys: a profile
.
Int J Epidemiol
.
2012
;
41
(
6
):
1602
1613
15
World Health Organization; United Nations Children’s Fund; US Agency for International Development; Academy for Educational Development; University of California at Davis; International Food Policy Research Institute
.
Indicators for Assessing Infant and Young Child Feeding Practices. Part 2 Measurement.
Geneva, Switzerland
:
World Health Organization
;
2010
.
16
Bhatta
DN
,
Glantz
S
.
Parental tobacco use and child death: analysis of data from Demographic and Health Surveys from South and South East Asian countries
.
Int J Epidemiol
.
2019
;
48
(
1
):
199
206
17
Sankar
MJ
,
Sinha
B
,
Chowdhury
R
, et al
.
Optimal breastfeeding practices and infant and child mortality: a systematic review and meta-analysis
.
Acta Paediatr
.
2015
;
104
(
467
):
3
13
18
de Francisco
A
,
Morris
J
,
Hall
AJ
,
Schellenberg
JRA
,
Greenwood
BM
.
Risk factors for mortality from acute lower respiratory tract infections in young Gambian children
.
Int J Epidemiol
.
1993
;
22
(
6
):
1174
1182
19
Hanson
LA
,
Ashraf
R
,
Zaman
S
,
Karlberg
J
,
Lindblad
BS
,
Jalil
F
.
Breast feeding is a natural contraceptive and prevents disease and death in infants, linking infant mortality and birth rates
.
Acta Paediatr
.
1994
;
83
(
1
):
3
6
20
Mølbak
K
,
Gottschau
A
,
Aaby
P
,
Højlyng
N
,
Ingholt
L
,
da Silva
AP
.
Prolonged breast feeding, diarrhoeal disease, and survival of children in Guinea-Bissau
.
BMJ
.
1994
;
308
(
6941
):
1403
1406
21
Ross
DA
,
Dollimore
N
,
Smith
PG
, et al;
Ghana VAST Study Team
.
Vitamin A supplementation in northern Ghana: effects on clinic attendances, hospital admissions, and child mortality [published correction appears in Lancet. 1993;342(8865):250]
.
Lancet
.
1993
;
342
(
8862
):
7
12
22
Garenne
M
,
Fontaine
O
.
Assessing probable causes of death using a standardized questionnaire: a study in rural Senegal
.
Bull World Health Organ
.
2006
;
84
(
3
):
248
253
23
Yoon
PW
,
Black
RE
,
Moulton
LH
,
Becker
S
.
Effect of not breastfeeding on the risk of diarrheal and respiratory mortality in children under 2 years of age in Metro Cebu, The Philippines
.
Am J Epidemiol
.
1996
;
143
(
11
):
1142
1148
24
de Rooy
L
,
Hawdon
J
.
Nutritional factors that affect the postnatal metabolic adaptation of full-term small- and large-for-gestational-age infants
.
Pediatrics
.
2002
;
109
(
3
).
25
Le Huërou-Luron
I
,
Blat
S
,
Boudry
G
.
Breast- v. formula-feeding: impacts on the digestive tract and immediate and long-term health effects
.
Nutr Res Rev
.
2010
;
23
(
1
):
23
36
26
Brandtzaeg
P
.
Mucosal immunity: integration between mother and the breast-fed infant
.
Vaccine
.
2003
;
21
(
24
):
3382
3388

Competing Interests

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.

Supplementary data