Influence of Mediterranean diet and screen time on vitamin D deficiency: Interim results from Hand aufs Herz Study

Background Vitamin D deficiency is the most common nutritional deficiency and appears to be linked with a higher incidence of cardiovascular disease. Furthermore, it’s regulating effect on blood pressure has been well studied. Changing dietary habits and increasing screen time are important factors affecting the health of today’s children and adolescents. Purpose This study aims to examine the effect of screen time and diet on vitamin D deficiency in school children. Methods As part of the prospective epidemiological study ‘Hand aufs Herz’, a comprehensive cardiovascular system check-up was conducted on German school children. Dietary behavior and screen time were assessed using a questionnaire, including the KIDMed 2.0 score for Mediterranean diet adherence. A total of 300 children aged 8 to 18 years agreed on a voluntary blood draw to assess vitamin D levels, 2 children were excluded from the analysis for taking vitamin D as dietary supplement. Statistical analyses were performed in R, v4.5.1. Results A total of 298 schoolchildren aged 8-18 years were included in the analysis (mean age 13.5±2.1 years, 54.4% male). Vitamin D deficiency was highly prevalent (44%); the mean blood vitamin D level was 20.4±6.1 ng/dl. There was a positive association between KIDMed score and vitamin D levels and a negative association between screen time and vitamin D levels, that did not reach statistical significance. Vitamin D levels among children with KIDMed score ≥8 meaning good adherence to Mediterranean diet and children with KIDMed score 4-7 (average adherence) is by 1.45 units and 0.44 units higher compared to children with KIDMed score < 3 points (poor adherence) (p>0.05). With each increasing hour of screen time during the weekdays and weekends, vitamin D levels decreased by 0.339 units and 0.298 units respectively (p>0.05). Children with KIDMed score ≥8 and children with KIDMed score 4-7 have 19% and 23% lower odds of having vitamin D deficiency compared to children with KIDMEed score < 3 points (p>0.05). Conclusion Excessive screen time and poor nutrition seems to be linked to vitamin D deficiency and thereby increase cardiovascular risk in school children. No statistical significance could be achieved with the available data, but a clear trend is nevertheless apparent. More data needs to be collected to investigate the influencing factors and impact of vitamin D deficiency in children. Public health efforts should enforce guidelines and promote healthy diets to positively influence the cardiovascular risk profile of children and adolescents.