Children with low vitamin D levels face a greater risk of early heart disease, according to a decades-long Finnish study. Could early supplementation shift the tide on cardiovascular prevention? Childhood 25-OH-vitamin D Levels Predict Early Cardiovascular Outcomes in Adulthood: The Cardiovascular Risk in Young Finns Study. Image Credit: Ekaterina Markelova / Shutterstock In a recent article published in the European Journal of Preventive Cardiology, researchers in Finland investigated whether low serum 25-hydroxyvitamin D (25-OH-vitamin D) levels in childhood are associated with the development of adult-onset atherosclerotic cardiovascular disease (ASCVD). Their findings suggest that low childhood vitamin D levels are independently associated with the development of early-onset ASCVD in adulthood. This research may identify an important early-life risk marker for cardiovascular disease, informing targeted prevention efforts. Background Previous observational studies in adults have shown that low serum vitamin D levels are associated with an increased risk of cardiovascular events. In an earlier paper, this team of Finnish researchers found that low vitamin D levels in childhood correlated with higher intima-media thickness of the carotid artery in adults. This is an established marker of atherosclerosis, indicating that plaque is gradually building up in artery walls. Eventually, this will cause the arteries to narrow and block the flow of blood. If the plaque bursts, it could lead to blood clots. Due to these mechanisms, vitamin D deficiencies could increase the risk of heart disease. However, it remains unclear whether low vitamin D levels during childhood could predict actual cardiovascular events in adulthood. About the study Researchers examined whether low serum 25-hydroxyvitamin D levels in childhood are associated with ASCVD. The hypothesis is grounded in emerging evidence that early-life exposures may affect long-term cardiovascular health. Given that vitamin D influences vascular and inflammatory pathways, this study aimed to investigate its potential role as an early-life risk marker for later cardiovascular events. The prospective cohort study used data from 3,516 participants of the Cardiovascular Risk in Young Finns Study. Serum 25-OH-vitamin D concentrations were assessed in 2010 using frozen serum samples originally collected in 1980, when participants were between 3 and 18 years old. The average childhood vitamin D level was 51.3 nmol/L, with a mean age at baseline of 10.5 years. Childhood measurements also included body mass index (BMI), lipid levels (specifically low-density lipoprotein [LDL], high-density lipoproteins [HDL], and triglycerides), blood pressure, dietary habits, socioeconomic status, smoking status, and physical activity. Cardiovascular events were tracked through linkage with national Finnish health registries, including the National Health Index and the Care Register for Health Care, up to 2018. A total of 95 participants (2.7%) experienced at least one ASCVD event, with a median age at onset of 47 years. Cox proportional hazard models were used to examine associations between different cut-off levels of childhood vitamin D and ASCVD risk in adulthood, adjusting for sex, age, and other conventional early-life risk factors. The study specifically analyzed several thresholds (cut-points) of vitamin D levels—31, 33, 35, 37, 39, 41, and 43 nmol/L—to assess which concentrations were most strongly associated with future ASCVD events. Findings Researchers found that low levels of 25-OH-vitamin D during childhood were significantly associated with a higher risk of adult-onset ASCVD events. Specifically, having childhood vitamin D levels below 31, 33, 35, or 37 nmol/L was linked to an increased risk of ASCVD in adulthood. For example, children with vitamin D levels below 35 nmol/L had more than double the risk of developing ASCVD compared to those with higher levels (hazard ratio, 2.19 [95% CI, 1.30–3.69]; adjusted for multiple risk factors). These associations remained significant even after adjusting for numerous childhood risk factors, including BMI, cholesterol, blood pressure, diet, and physical activity. These associations remained consistent in additional analyses, including propensity score matching and adjusting for adult vitamin D levels. Nearly one-fifth of the cohort had vitamin D levels below 37 nmol/L during childhood. The results suggest that suboptimal vitamin D status in early life is associated with an increased cardiovascular risk decades later, independent of other known risk factors. The study also explored potential mechanisms, noting that vitamin D receptors are present throughout the vascular system and that vitamin D’s active form may help reduce inflammation, regulate blood pressure, and slow vascular aging, all of which could influence long-term cardiovascular health. Conclusions This study suggests that low levels of vitamin D in childhood are independently associated with early-onset ASCVD in adulthood, highlighting a potential early-life risk marker for cardiovascular disease. The findings support current recommendations for maintaining adequate vitamin D levels in children and could inform preventive strategies. The study's strengths include a large, population-based cohort with long-term follow-up, robust health registry data, and a comprehensive assessment of childhood cardiovascular risk factors. However, limitations include potential measurement error from using serum samples stored for 30 years, though vitamin D is relatively stable under such conditions. The cohort was ethnically homogenous (white Europeans), limiting generalizability. Also, at follow-up, the participants were still relatively young, and many had not yet reached the ages at which ASCVD becomes more prevalent, warranting continued observation. Additionally, the study's observational nature precludes establishing a direct causal relationship between childhood vitamin D levels and subsequent cardiovascular events. In conclusion, the study provides early-life evidence linking vitamin D status with adult cardiovascular health. Optimizing vitamin D intake during childhood may offer a low-cost and easily implemented strategy for reducing long-term ASCVD risk; however, further research, including randomized trials, will be needed to confirm causality and refine recommendations.