Vitamin D in Children: Can We Do Better?

Severe vitamin D deficiency in children can result in nutritional rickets, which causes softening and weakening of the bones and is associated with impaired growth, developmental delays, and hypocalcemic seizures.¹  Nutritional rickets, a largely preventable condition, can result in limb deformity, scoliosis, dental abnormalities, and fractures.¹  In 2008, in an effort to prevent vitamin D deficiency and rickets in children in the United States, the American Academy of Pediatrics (AAP) increased the recommended daily intake of vitamin D for infants from 200 to 400 IU.¹ 

In the current issue of Pediatrics, investigators Simon and Ahrens²  report that since 2009, the percentage of US infants who meet the AAP’s guidelines for vitamin D intake has not increased.¹  The guidelines were met by only 27% of infants overall and by <40% of infants in nearly all demographic subgroups.²  Probable impediments to meeting the AAP guidelines include a combination of inconsistent prescribing by clinicians and poor adherence to the use of a supplement by parents of infants, and this is further complicated by a lack of awareness of the consequences of vitamin D deficiency in infants among the public.

Higher use of vitamin D supplementation in infants has been reported in Canada. In one study, 80% of 2-month-old infants were supplemented with vitamin D.³  Investigators reported that higher breastfeeding rates and the lack of sunlight in the winter months due to Canada’s higher latitude may have created a greater impetus for vitamin D supplementation along with a heightened awareness among both parents and clinicians.³  Notably, participants reported that in addition to clinicians, vitamin D supplementation was recommended by prenatal providers, dieticians, pharmacists, family members, or friends.³ 

Vitamin D supplementation in infants is commonly prescribed as a daily 1-mL dose of liquid. Concerns about the 1-mL dropper have included inconsistent precision and infants gagging on the liquid.⁴  Some suggested alternatives have included different formulations of vitamin D and supplementation of breastfeeding mothers. Investigators in Canada found that parents and infants preferred either 400 IU of vitamin D provided in dissolving filmstrips or concentrated vitamin D administered as 1 drop to 1 mL of liquid administered by a dropper.^3,4  Data suggest that supplementing mothers of exclusively breastfed infants with vitamin D can provide adequate levels of vitamin D in infants in the first month of life, but more research is needed.⁵ 

In low- and middle-income countries with a higher prevalence of vitamin D deficiency than the United States, a public health approach has included mandatory fortification of staple foods in addition to supplementation of at-risk subgroups.^6–8  Other public health initiatives to address vitamin D deficiency have revealed mixed results.^9–12  In Turkey, a program to distribute free vitamin D to families for up to 1 year in addition to education of health care workers and clinicians contributed to a marked decrease in the prevalence of rickets (6.0% in 1998 to 0.1% in 2008).⁹  Conversely, in a Canadian study, a program for free vitamin D prescriptions for infants did not improve either participation or adherence.¹⁰  In the United Kingdom, programs that provided coupons by mail for families to redeem for vitamin supplements and even for delivery of vitamin D at the first postnatal home visit had lower-than-expected uptake.¹¹  In one UK study of a free vitamin D supplementation program, there was a decrease in cases of symptomatic vitamin D deficiency despite low participation (17%) in the program, a change that investigators attributed to increased public awareness.¹² 

To standardize prescribing practices, alerts through the electronic health record may be helpful but should be approached with caution because of concerns about alert fatigue. In addition to the primary medical home, there are other points of contact within the health care system that are underused in which counseling and/or prescribing of vitamin D could occur. These include the newborn nursery, ambulatory settings (both urgent and subspecialty clinics), inpatient settings, pharmacies, and local or state programs, such as the Special Supplemental Nutrition Program for Women, Infants, and Children and early intervention programs that support infant nutrition and development.

Despite lower-than-expected adherence, presumably, most infants in Simon and Ahrens’²  study did not develop severe vitamin D deficiency, which suggests that there may be some, although perhaps not daily, vitamin D supplementation occurring or that other sources of dietary vitamin D may be helping. It is unknown how many children in the study actually had vitamin D sufficiency (levels of vitamin D capable of supplying the body’s need for normal bone metabolism). The study is a call to action for the pediatric community to rethink and to reassess its approaches to optimizing vitamin D supplementation for infants. Additional research is needed to better understand prescribing patterns, barriers to adherence by parents of infants, and alternate strategies for vitamin D supplementation to inform novel public health programs in the United States.