Vitamin D status and dental caries in healthy Swedish children

Randomized controlled trial (DViSUM) in healthy Swedish children. Participants were 6 years old at enrollment (n=206) from northern and southern Sweden, including both fair and darker skin complexions and regular milk consumers. Eight-year-old children who had participated in the vitamin D intervention at age 6 were invited for a dental follow-up; 85 completed the dental examination. Data collected included caries and enamel defects, health/diet/behavior questionnaires, saliva LL37, and detection of cariogenic bacteria.

Vitamin D3 in a milk-based supplement, taken daily for 3 months; dosing arms: 25 μg/day, 10 μg/day, or 2 μg/day (placebo).

Higher 25(OH)D status at age 6 was associated with lower odds of caries at age 8 (OR ≈ 0.96 per 1 nmol/L increase; p = 0.024) in the basic model, but the association weakened after adjusting for BMI and vitamin D supplement intake and was not significant after correction for small-sample bias. Similar results were observed using vitamin D status after the 3-month intervention. Enamel defects showed no association with vitamin D status. Vitamin D status was positively associated with saliva LL37 levels; caries presence was associated with higher LL37, suggesting a microbiota-related response. Overall, findings support a potential inverse relationship between vitamin D status and caries, but are not conclusive due to small sample size and attenuation after adjustments; replication in larger, longitudinal studies is warranted. Vitamin D status did not affect enamel defects but may relate to innate immunity via LL37.

Small dental-follow-up sample (n=85) with limited power; follow-up participants may not be representative of the original cohort; vitamin D status not repeatedly measured across the entire interval; potential response bias in questionnaires; study population selected for vitamin D supplementation in early life and regular dental care limits generalizability; potential selection bias in the follow-up group; observational design limits causal inference.