BACKGROUND:

The association of dietary fat distribution with markers of subclinical atherosclerosis during early life is unknown. We examined whether success in achieving the main target of an infancy-onset dietary intervention based on the distribution of dietary fat was associated with aortic and carotid intima-media thickness (IMT) and distensibility from childhood to young adulthood.

METHODS:

In the prospective randomized controlled Special Turku Coronary Risk Factor Intervention Project trial, personalized dietary counseling was given biannually to healthy children from infancy to young adulthood. The counseling was based on Nordic Nutrition Recommendations, with the main aim of improving the distribution of dietary fat in children’s diets. IMT and distensibility of the abdominal aorta and common carotid artery were measured repeatedly at ages 11 (n = 439), 13 (n = 499), 15 (n = 506), 17 (n = 477), and 19 years (n = 429). The targeted distribution of dietary fat was defined as a ratio of saturated fatty acids to monounsaturated and polyunsaturated fatty acids of <1:2 and as an intake of saturated fatty acids of <10% of energy intake. Participants who met ≥1 of these 2 criteria were defined to achieve the main intervention target.

RESULTS:

Individuals who achieved the main intervention target had lower aortic IMT (age- and sex-adjusted mean difference 10.4 µm; 95% confidence interval: 0.3 to 20.5 µm) and better aortic distensibility (0.13% per 10 mm Hg; 95% confidence interval: 0.00% to 0.26% per10 mm Hg) compared with their peers who did not meet the target.

CONCLUSIONS:

Achieving the main target of an infancy-onset dietary intervention, reflecting dietary guidelines, was favorably associated with aortic IMT and distensibility during the early life course. These data support the recommendation of favoring unsaturated fat to enhance arterial health.

What’s Known on This Subject:

Increased arterial intima-media thickness (IMT) and decreased arterial distensibility are subclinical markers of atherosclerosis and independently predict cardiovascular outcomes. The association of dietary fat distribution with arterial IMT and distensibility in early life has not been investigated.

What This Study Adds:

These prospective data reveal that better dietary fat distribution, defined by favoring unsaturated fat, was beneficially associated with aortic IMT and distensibility. There results suggest that achieving better dietary fat distribution enhances arterial health in healthy children and adolescents.

Development of atherosclerosis begins during early life and is greatly affected by the presence and intensity of risk factors.1  Adverse subclinical functional and structural changes of the arteries are seen already in childhood, and some of these changes can be assessed by using noninvasive ultrasound methods. These surrogate markers of atherosclerosis, such as intima-media thickness (IMT) and arterial distensibility, have been shown to independently predict future clinical cardiovascular events.1,2 

Dietary composition is known to affect cardiovascular risk levels already in childhood, and guidelines universally encourage consumption of unsaturated fats and avoidance of excess saturated fat.38  The Special Turku Coronary Risk Factor Intervention Project (STRIP) is a prospective randomized controlled trial that has conducted a unique dietary intervention based on Nordic Nutrition Recommendations from infancy to adulthood.9  The intervention comprised repeated individualized dietary counseling with the main aim of improving the distribution of dietary fat (ie, replacing intake of saturated fat with unsaturated fat) in children’s diets. Recently, we reported that achieving the targets of the dietary intervention was associated with better insulin sensitivity and a more favorable lipid profile from childhood to adulthood.10  However, it is not known whether achieving the dietary targets, which are based on the distribution of dietary fat, is associated with arterial IMT and distensibility.

In this study, using data from the STRIP study, we examined how the success of achieving the main intervention target, reflecting dietary guidelines of fat distribution, was associated with arterial IMT and distensibility at the ages 11, 13, 15, 17, and 19 years. These data are of utmost importance because there has been no study to investigate whether the dietary fat distribution is associated with subclinical markers of atherosclerosis in early life.

For detailed methods, please see the Supplemental Information.

The STRIP study is a prospective randomized controlled trial to prevent atherosclerosis beginning in infancy. The study subjects were enrolled at their 5-month visit at Turku City well-baby clinics, where the recruitment was performed by nurses (Supplemental Fig 5). No risk group targeting was performed at recruitment. Of the eligible age cohort, 1062 infants (56.5%; born in 1989–1991) were allocated to dietary intervention (n = 540) or control (n = 522) groups by random numbers at the 7-month visit. Twins were randomly assigned together. The participants were nonblinded to the group allocation. The intervention and control groups included a similar proportion of boys and girls, and the baseline characteristics did not differ between the study groups in any assessable way.9  The intervention group received individualized dietary counseling at least biannually beginning at the age of 8 months until the age of 20 years.9,11  The main aim of the intervention was to replace saturated fat with unsaturated fat in the diet. The control group was seen biannually until the age of 7 years and annually thereafter until 20 years of age.9  For details of the intervention given in the STRIP study, please see the Supplemental Information.

Children with type 1 diabetes (n = 6), familial hypercholesterolemia (n = 3), and congenital physical impairment (n = 5) were excluded from the analyses of this study. After these exclusions, the current study comprised healthy children (ie, they were not regarded as in a risk group for atherosclerosis development) who provided arterial ultrasound data at ages 11 (n = 439), 13 (n = 499), 15 (n = 506), 17 (n = 477), or 19 years (n = 429).

The STRIP study is conducted according to the guidelines of the Declaration of Helsinki, and the study protocol was approved by the local ethics committee. Written informed consent was received from the participants’ parents in the beginning of the study. Later, at the ages of 15 and 18 years, the participants gave their own informed consent.

Food consumption was recorded by using a 4-day food record (consecutive days; at least 1 weekend day included).12  A dietitian checked the food records for accuracy, and the food and nutrient intakes were analyzed with a continuously updated Micro Nutrica program.13 

According to the main nutritional targets of the dietary intervention given in the study, which was based on the latest Nordic Nutrition Recommendations available at the time, and also reflecting current dietary guidelines,3,4  we defined the targeted distribution of dietary fat using 2 separate criteria: a ratio of saturated fatty acids (SAFAs) to monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) of <1:2 and an intake of SAFAs of <10% of energy intake (E%). Participants who met ≥1 of these 2 criteria were defined to achieve the main intervention target. For details of the dietary data, please see the Supplemental Information.

The study outcomes, IMT and distensibility of the abdominal aorta and common carotid artery, were studied with ultrasonography (Acuson Sequoia 512 mainframe; Acuson, Mountain View, CA) at ages 11, 13, 15, 17, and 19 years, as previously described.11,14 

The association of the STRIP study group (intervention and control) with the probability of meeting the main intervention target was studied with a modified Poisson regression model with generalized estimating equation estimation for repeated measures (risk ratios [RRs] calculated for the STRIP intervention versus control group; adjusted for age and sex). Associations of the STRIP study group and achieving the main intervention target, regardless of the STRIP study group allocation, with arterial IMT and distensibility were studied with a linear mixed-effects model for repeated measures. All models included age and sex as covariates. The association of cumulative success in achieving the main intervention target, regardless of the original STRIP study group allocation, beginning at age 13 months and aortic IMT was studied by comparing those participants who had never achieved the target and those in the uppermost 10th and fifth percentiles for achieving the target by using repeated-measures analysis of covariance adjusted for age and sex. Statistical significance was inferred at a 2-tailed P < .05. All statistical analyses were performed with SAS version 9.4 (SAS Institute, Inc, Cary, NC).

Characteristics of study participants in the intervention and control groups are shown in Table 1.

TABLE 1

Characteristics of Study Participants at 11 and 19 y of Age Among Intervention and Control Groups

Age 11 yAge 19 y
InterventionControlInterventionControl
nMeanSDnMeanSDnMeanSDnMeanSD
BMI 262 17.8 2.6 278 18.1 3.1 202 22.2 3.3 240 22.7 4.1 
Systolic blood pressure, mm Hg 262 106 10 278 106 10 201 121 13 242 121 14 
Diastolic blood pressure, mm Hg 262 58 278 59 201 65 242 66 
Total cholesterol, mmol/L 261 4.42 0.65 274 4.58 0.80 199 4.26 0.77 241 4.36 0.81 
LDL cholesterol, mmol/L 261 2.74 0.56 273 2.89 0.69 198 2.43 0.61 241 2.57 0.71 
HDL cholesterol, mmol/L 261 1.32 0.27 273 1.29 0.27 198 1.34 0.29 241 1.30 0.31 
Triglycerides, mmol/L 261 0.8 0.4 274 0.82 0.45 199 1.09 0.65 241 1.09 0.46 
Non-HDL cholesterol, mmol/L 261 3.10 0.59 273 3.28 0.75 198 2.91 0.67 241 3.07 0.76 
SAFA intake, E% 233 11.3 2.6 252 13.2 2.7 139 11.5 2.5 203.0 12.4 3.0 
SAFA/(MUFA + PUFA) 233 0.67 0.15 252 0.84 0.18 139 0.67 0.16 203 0.76 0.19 
PUFA/SAFA 233 0.56 0.18 252 0.41 0.13 139 0.58 0.18 203 0.52 0.23 
Dietary cholesterol, mg 233 187 76 252 204 76 139 213 128 203 217 110 
Dietary fiber, g/MJ 233 2.01 0.48 252 1.86 0.47 139 2.21 0.66 203 2.05 0.80 
Age 11 yAge 19 y
InterventionControlInterventionControl
nMeanSDnMeanSDnMeanSDnMeanSD
BMI 262 17.8 2.6 278 18.1 3.1 202 22.2 3.3 240 22.7 4.1 
Systolic blood pressure, mm Hg 262 106 10 278 106 10 201 121 13 242 121 14 
Diastolic blood pressure, mm Hg 262 58 278 59 201 65 242 66 
Total cholesterol, mmol/L 261 4.42 0.65 274 4.58 0.80 199 4.26 0.77 241 4.36 0.81 
LDL cholesterol, mmol/L 261 2.74 0.56 273 2.89 0.69 198 2.43 0.61 241 2.57 0.71 
HDL cholesterol, mmol/L 261 1.32 0.27 273 1.29 0.27 198 1.34 0.29 241 1.30 0.31 
Triglycerides, mmol/L 261 0.8 0.4 274 0.82 0.45 199 1.09 0.65 241 1.09 0.46 
Non-HDL cholesterol, mmol/L 261 3.10 0.59 273 3.28 0.75 198 2.91 0.67 241 3.07 0.76 
SAFA intake, E% 233 11.3 2.6 252 13.2 2.7 139 11.5 2.5 203.0 12.4 3.0 
SAFA/(MUFA + PUFA) 233 0.67 0.15 252 0.84 0.18 139 0.67 0.16 203 0.76 0.19 
PUFA/SAFA 233 0.56 0.18 252 0.41 0.13 139 0.58 0.18 203 0.52 0.23 
Dietary cholesterol, mg 233 187 76 252 204 76 139 213 128 203 217 110 
Dietary fiber, g/MJ 233 2.01 0.48 252 1.86 0.47 139 2.21 0.66 203 2.05 0.80 

HDL, high-density lipoprotein; LDL, low-density lipoprotein.

Participants in the intervention group had a higher probability of meeting the main intervention target between ages 11 and 19 years (Fig 1; mean proportion of participants who met the target: intervention group, 37.7%; control group, 17.8%). Between ages 13 months and 10 years, the mean proportion of participants achieving the target was 34.9% and 7.9% in the intervention and control groups, respectively (RR = 4.33; 95% confidence interval [CI]: 3.56 to 5.27; P < .0001). No statistically significant differences between the intervention and control groups were detected in IMT or in distensibility, as we have previously reported (Table 2).15 

FIGURE 1

Proportions of participants meeting the main intervention target, which was based on the distribution of dietary fat, from 11 to 19 years of age in the intervention and control groups. The targeted distribution of dietary fat was defined as 2 separate criteria: a ratio of SAFAs/(MUFAs + PUFAs) of <1:2 and an intake of SAFAs of <10E%. Participants who met ≥1 of these 2 criteria were defined to achieve the main intervention target. The risk ratio indicating the probability of meeting the main intervention target in the intervention group in comparison with the control group was 2.15 (95% CI 1.80 to 2.56; P for difference < .0001).

FIGURE 1

Proportions of participants meeting the main intervention target, which was based on the distribution of dietary fat, from 11 to 19 years of age in the intervention and control groups. The targeted distribution of dietary fat was defined as 2 separate criteria: a ratio of SAFAs/(MUFAs + PUFAs) of <1:2 and an intake of SAFAs of <10E%. Participants who met ≥1 of these 2 criteria were defined to achieve the main intervention target. The risk ratio indicating the probability of meeting the main intervention target in the intervention group in comparison with the control group was 2.15 (95% CI 1.80 to 2.56; P for difference < .0001).

Close modal
TABLE 2

Mean Aortic and Carotid IMT and Distensibility Between 11 and 19 years of Age According to STRIP Study Groups (Intervention and Control) and According to Success in Achieving the Main Intervention Target, Based on Distribution of Dietary Fat, Regardless of the STRIP Study Group

STRIP Study GroupSuccess in Achieving the Main Intervention Target
Control GroupIntervention GroupPTarget Not AchievedTarget AchievedP
Adjusted MeanaSEAdjusted MeanaSEAdjusted MeanaSEAdjusted MeanaSE
Aortic IMT, µm 521.4 3.3 524.3 3.4 .54 524.9 2.8 514.5 4.5 .043 
Carotid IMT, µm 438.1 1.9 439.1 1.9 .69 436.9 1.6 438.8 2.3 .44 
Aortic distensibility, % per mm Hg 3.89 0.05 3.99 0.05 .14 3.89 0.04 4.02 0.06 .049 
Carotid distensibility, % per mm Hg 3.84 0.03 3.85 0.03 .68 3.84 0.03 3.84 0.04 .996 
STRIP Study GroupSuccess in Achieving the Main Intervention Target
Control GroupIntervention GroupPTarget Not AchievedTarget AchievedP
Adjusted MeanaSEAdjusted MeanaSEAdjusted MeanaSEAdjusted MeanaSE
Aortic IMT, µm 521.4 3.3 524.3 3.4 .54 524.9 2.8 514.5 4.5 .043 
Carotid IMT, µm 438.1 1.9 439.1 1.9 .69 436.9 1.6 438.8 2.3 .44 
Aortic distensibility, % per mm Hg 3.89 0.05 3.99 0.05 .14 3.89 0.04 4.02 0.06 .049 
Carotid distensibility, % per mm Hg 3.84 0.03 3.85 0.03 .68 3.84 0.03 3.84 0.04 .996 
a

Adjusted for age and sex.

Age- and sex-adjusted means of aortic and carotid IMT and distensibility between 11 and 19 years of age among participants who achieved and who did not achieve the main intervention target, regardless of the original study group allocation (intervention or control), are shown in Table 2. Participants who achieved the main intervention target had lower aortic IMT between 11 and 19 years of age (age- and sex-adjusted mean difference: 10.4 µm [95% CI: 0.3 to 20.5 µm]) compared with their peers who did not meet the target (Table 2, Fig 2). Furthermore, participants who achieved the main intervention target had, on average, better aortic distensibility between 11 and 19 years of age (age- and sex-adjusted mean difference: 0.13% per 10 mm Hg [95% CI: 0.0% to 0.26% per 10 mm Hg]) compared with those who did not meet the target (Table 2, Fig 3). Contrary to the favorable association with indices of the aorta, achieving the main intervention target was not associated with carotid IMT or distensibility.

FIGURE 2

IMT of the abdominal aorta (aortic IMT) and carotid artery (carotid IMT) among participants who achieved and who did not achieve the main intervention target, which was based on the distribution of dietary fat, from 11 to 19 years of age. The targeted distribution of dietary fat was defined as 2 separate criteria: a ratio of SAFAs/(MUFAs + PUFAs) of <1:2 and an intake of SAFAs <10E%. The main intervention target was defined as meeting ≥1 of these 2 criteria. The age- and sex-adjusted P value (main intervention target achieved versus not achieved) was .043 for aortic IMT and .44 for carotid IMT. In the box plots, the end of the whiskers indicate the fifth and 95th percentiles, the upper box indicates the upper quartile, the lower box indicates the lower quartile, the band represents the median, and the circle indicates the mean.

FIGURE 2

IMT of the abdominal aorta (aortic IMT) and carotid artery (carotid IMT) among participants who achieved and who did not achieve the main intervention target, which was based on the distribution of dietary fat, from 11 to 19 years of age. The targeted distribution of dietary fat was defined as 2 separate criteria: a ratio of SAFAs/(MUFAs + PUFAs) of <1:2 and an intake of SAFAs <10E%. The main intervention target was defined as meeting ≥1 of these 2 criteria. The age- and sex-adjusted P value (main intervention target achieved versus not achieved) was .043 for aortic IMT and .44 for carotid IMT. In the box plots, the end of the whiskers indicate the fifth and 95th percentiles, the upper box indicates the upper quartile, the lower box indicates the lower quartile, the band represents the median, and the circle indicates the mean.

Close modal
FIGURE 3

Distensibility of the abdominal aorta (aortic distensibility) and carotid artery (carotid distensibility) among participants who achieved and who did not achieve the main intervention target, which was based on the distribution of dietary fat, from 11 to 19 years of age. The targeted distribution of dietary fat was defined as 2 separate criteria: a ratio of SAFAs/(MUFAs + PUFAs) of <1:2 and an intake of SAFAs <10E%. Achieving the main intervention target was defined as meeting ≥1 of these 2 criteria. The age- and sex-adjusted P value (main intervention target achieved versus not achieved) was .049 for aortic distensibility and .996 for carotid distensibility. In the box plots, the end of the whiskers indicate the fifth and 95th percentiles, the upper box indicates the upper quartile, the lower box indicates the lower quartile, the band represents the median, and the circle indicates the mean.

FIGURE 3

Distensibility of the abdominal aorta (aortic distensibility) and carotid artery (carotid distensibility) among participants who achieved and who did not achieve the main intervention target, which was based on the distribution of dietary fat, from 11 to 19 years of age. The targeted distribution of dietary fat was defined as 2 separate criteria: a ratio of SAFAs/(MUFAs + PUFAs) of <1:2 and an intake of SAFAs <10E%. Achieving the main intervention target was defined as meeting ≥1 of these 2 criteria. The age- and sex-adjusted P value (main intervention target achieved versus not achieved) was .049 for aortic distensibility and .996 for carotid distensibility. In the box plots, the end of the whiskers indicate the fifth and 95th percentiles, the upper box indicates the upper quartile, the lower box indicates the lower quartile, the band represents the median, and the circle indicates the mean.

Close modal

Because the achievement of the main intervention target revealed association with the aortic IMT and distensibility, we further studied these associations in more detail. The association of cumulative success in achieving the main intervention target beginning at age 13 months and aortic IMT was studied by comparing those participants who had never achieved the target and those in the uppermost 10th and fifth percentiles for achieving the target, respectively. The age- and sex-adjusted mean difference in aortic IMT between those who had not achieved the target and those in the uppermost 10th percentile was 18.1 µm (95% CI: 1.5 to 34.7 µm). The difference further increased when the comparison was made with those in the uppermost fifth percentile (mean difference: 23.0 µm [95% CI: 3.0 to 43.1 µm]). When these analyses were done for aortic distensibility, no significant associations were found.

Because of the consistent association observed between the main intervention target and aortic IMT, we further explored this association. First, when the analyses shown in Fig 2 were adjusted for dietary cholesterol and fiber intake (E%), the results remained essentially similar (age- and sex-adjusted mean differences for those achieving and those failing to meet the target: 10.4 µm [95% CI: 0.1 to 20.7 µm] and 8.5 µm [95% CI: −1.9 to 18.9 µm], respectively).

To gain insights into which of the individual dietary fat components are responsible for the association with aortic IMT, we analyzed the associations of cumulative SAFA, MUFA, and PUFA intake with this vascular marker. These analyses revealed a trend for decreasing aortic IMT when the intake of SAFA decreased (Fig 4). Participants whose SAFA intake was <10E%, following recommendations, had a lower IMT than those peers whose intake of SAFA was more than 12E%. The intakes of PUFA or MUFA revealed no associations with aortic IMT.

FIGURE 4

Saturated fat intake beginning from the age of 13 months (cumulative SAFA E%) and aortic IMT between the ages of 11 and 19 years. Participants with a cumulative SAFA E% of ≤9.5E% and ≤10E%, respectively, had a lower aortic IMT than those with a cumulative SAFA E% of >12E% (P = .010 and P = .015, respectively). n values for observations between the ages of 11 and 19 years were 47 for a cumulative SAFA E% of ≤9E%, 77 for a cumulative SAFA E% of >9E%–≤9.5E%, 92 for a cumulative SAFA E% of >9.5E%–≤10E%, 710 for a cumulative SAFA E% of >10E%–≤12E%, and 1373 for a cumulative SAFA E% of ≥12E%.

FIGURE 4

Saturated fat intake beginning from the age of 13 months (cumulative SAFA E%) and aortic IMT between the ages of 11 and 19 years. Participants with a cumulative SAFA E% of ≤9.5E% and ≤10E%, respectively, had a lower aortic IMT than those with a cumulative SAFA E% of >12E% (P = .010 and P = .015, respectively). n values for observations between the ages of 11 and 19 years were 47 for a cumulative SAFA E% of ≤9E%, 77 for a cumulative SAFA E% of >9E%–≤9.5E%, 92 for a cumulative SAFA E% of >9.5E%–≤10E%, 710 for a cumulative SAFA E% of >10E%–≤12E%, and 1373 for a cumulative SAFA E% of ≥12E%.

Close modal

With this study, we are the first to report the association of success in achieving the main target of an infancy-onset dietary intervention with repeatedly assessed markers of subclinical atherosclerosis. We show that participants who achieve the main intervention target, reflecting dietary guidelines, have lower aortic IMT and better aortic distensibility from childhood to early adulthood. These data are unique because of the exceptional dietary data meticulously collected since infancy and the concurrent assessment of markers of subclinical atherosclerosis. The reported findings are clinically important because increased arterial IMT predicts future cardiovascular events and is associated with higher cardiovascular mortality.1  In addition, decreased arterial distensibility is associated with conventional cardiovascular disease risk factors, and it is an independent predictor of cardiovascular events.2 

In STRIP, the main aim of the infancy-onset dietary counseling was to improve the distribution of dietary fat in children’s diets. Previous reports have revealed that this has been successful: the average SAFA intake has been lower in the intervention children compared with their control peers.16  In this study, we observed that participants in the intervention group had a higher probability of achieving the main intervention target, defined as SAFA/(MUFA + PUFA) <1:2 and/or SAFA <10E%, compared with their peers in the control group. However, the proportion of participants in the intervention group meeting the main intervention target is relatively low (38%). A similar result revealing low prevalence of children meeting the recommended dietary fat distribution targets in response to counseling was observed in the Physical Activity and Nutrition in Children Study, in which the target of SAFA <10E% was met by 24% of the participants aged 6 to 8 years.17  Likewise, the mean intake of SAFA (13E%) was above the recommended levels in all time points in 1- to 6-year-old participants of a large population-based cohort study, the Type 1 Diabetes Prediction and Prevention Project.18  In addition, in the Finnish Diabetes Prevention Study, 26% of adults in the intervention group and 11% in the control group achieved the target of SAFA <10E%.19  Although the rates in achieving the recommended dietary fat distribution are relatively low, it is important to bear in mind that Finns, including children, have had diets rich in SAFA and low in unsaturated fat, as indicated, for example, by the PUFA-to-SAFA ratio of 0.24 in 1980.20  The rather low target achievement rates in the STRIP intervention group, coupled with 18% of control children meeting the target, reduces the power to detect the effects of having recommended dietary fat distribution if the analyses are restricted to direct comparisons between the intervention and control groups. This may offer one explanation why statistically significant differences in IMT and distensibility are not seen between the intervention and control groups. An alternative way to examine the effects of diet on vascular health is to treat the STRIP participants as a cohort and compare individuals on the basis of their dietary characteristics regardless of their study group allocation. Using such an approach, we show here that achieving the main intervention target, which was based on nutrition recommendations, is favorably associated with aortic IMT and distensibility.

In this study, dietary fat distribution was associated with aortic vascular measures but not with carotid indices. Autopsy studies have revealed that the earliest morphologic alterations in the arterial wall emerge in the abdominal aorta.21  Therefore, aortic IMT and distensibility may be better markers for subclinical atherosclerosis in childhood compared with the respective carotid indices at this young age. Here, we observed a difference of 10.4 µm in aortic IMT between those who achieved and those who failed to meet the main intervention target at the ages of 11 to 19 years. When cumulative success in achieving the main intervention target beginning from the age of 13 months and aortic IMT was studied by comparing participants who had never achieved the target and those in the uppermost 10th and fifth percentiles for achieving the target, the differences in aortic IMT were markedly larger (18.1 and 23.0 µm, respectively). Of the individual dietary fat components, the cumulative intake of SAFA revealed inverse association with aortic IMT. However, in these cumulative analyses, no significant associations were found for aortic distensibility. These results suggest that aortic distensibility, as a marker of functional impairment of the arterial wall, may be more prone to the current dietary fat distribution, whereas structural changes in the arterial wall (IMT) become more detectible when cumulative exposure of dietary fat distribution is taken into account.

Potential limitation of the STRIP trial is unavoidable selection bias in the initial recruitment of participants, in which families that took part in the trial might have been more interested in health issues. Moreover, although the control group children did not receive dietary counseling, they probably were more aware of their health-related factors than typical Finnish children. The control families completed food records similar to the intervention peers and received their serum cholesterol values, which could have inadvertently caused them to modify their behavior and diet. Indeed, we have observed during follow-up that the control group has approached to the intervention group with respect to the distribution of dietary fat.16  Such potential biases may have diluted the differences between intervention and control groups. Second, we used pulse pressure measured from the brachial artery, not from the artery in question, for the calculation of aortic and carotid distensibility. This is a limitation because the use of brachial pressures may overestimate pulse pressure in central arteries. However, the difference between central and peripheral pulse pressure is likely to be similar between study subjects within a narrow age range,22  as in the current study. Furthermore, an excellent correlation between systolic and diastolic blood pressures measured invasively from the ascending aorta and those measured noninvasively from the brachial artery has been shown.23  Third, during such an extensive follow-up period, it is inevitable that loss to follow-up occurred. We have previously reported that no systematic differences in key study variables, such as total cholesterol levels or weight, have been found in those continuing in the study and those lost to follow-up.9,24,25  In addition, a recent attrition analysis revealed that at the age of 20 years, men less often provided dietary data compared with women, and men who had completed the food records had lower BMI than men who did not complete food records, but no other differences in cardiovascular risk factor levels were observed.10  Therefore, we do not suspect that a systematic selection bias would have influenced the observed results. Fourth, because children in the STRIP study are all white, the results may not be generalizable to other ethnicities. Major strengths of the study are the uniquely long intervention and follow-up period, beginning in infancy; the large number of repeatedly studied participants; and the use of well-established methods, including in vivo assessment of early markers of atherosclerosis.

Better dietary fat distribution, reflecting dietary guidelines, was favorably associated with aortic IMT and distensibility from childhood to young adulthood. These data importantly lend evidence that achieving better dietary fat distribution, defined by favoring unsaturated fat, in part enhances arterial health in healthy children and adolescents. The findings support recent dietary recommendations in the promotion of cardiovascular health.3,4 

We acknowledge Noora Kartiosuo from the Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku for statistical advice with these data.

Dr Laitinen substantially contributed to the conception and the design of the study, researched the data, wrote the manuscript, and reviewed the manuscript critically for important intellectual content; Drs Nuotio and Magnussen substantially contributed to the conception and the design of the study, contributed to the discussion, and reviewed the manuscript critically for important intellectual content; Drs Rovio, Niinikoski, Juonala, Viikari, Rönnemaa, Jokinen, Lagström, Jula, and Simell substantially contributed to the conception and the study design, acquired data, contributed to the discussion, and reviewed the manuscript critically for important intellectual content; Drs Raitakari and Pahkala substantially contributed to the conception and the study design, acquired and researched the data, drafted the manuscript, and reviewed the manuscript critically for important intellectual content; and all authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

This trial has been registered at www.clinicaltrials.gov (identifier NCT00223600).

Deidentified individual participant data will not be made available.

FUNDING: The Special Turku Coronary Risk Factor Intervention Project study is funded by the Academy of Finland (grants 206374, 294834, 251360, 275595, and 322112), the Juho Vainio Foundation, the Finnish Foundation for Cardiac Research, the Finnish Ministry of Education and Culture, the Finnish Cultural Foundation, the Sigrid Jusélius Foundation, Special Governmental Grants for Health Sciences Research (Turku University Hospital), the Yrjö Jahnsson Foundation, and the Turku University Foundation. Dr Magnussen is supported by a National Heart Foundation of Australia Future Leader Fellowship (100849).

CI

confidence interval

E%

percent of energy intake

IMT

intima-media thickness

MUFA

monounsaturated fatty acid

PUFA

polyunsaturated fatty acid

RR

risk ratio

SAFA

saturated fatty acid

STRIP

Special Turku Coronary Risk Factor Intervention Project

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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.

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