Is There a Need for Vitamin D Supplements During Summer Time in Northern Germany? A Study of Hospitalised Fracture Patients.

Background/objectives: Vitamin D is a key factor in bone metabolism, especially in patients who have suffered fractures, a group in need of a healthy bone metabolism. In Germany, a 70-year-old person requires 20 min of sun exposure daily for sufficient endogenous production in April. While this appears to be a sufficient period on paper, it raises the question of whether sufficient synthesis is achieved, given the time and the implementation of skin cancer prevention. Furthermore, it is necessary to determine whether self-medication is a safe option.

Methods: This was an analysis of vitamin D levels in patients with fractures over a one-year period. To avoid bias due to vitamin D intake, patients were divided into groups (self-medication, without, prescribed). The differences due to age, gender, fracture type and fluctuation over the year were analysed.

Results: 613 patients with a mean age of 73 years (45-97) were enrolled. The mean vitamin D level across all groups was 51 nmol/L, with a mean of 40 nmol/L for patients without supplementation ( = 449). Monthly comparisons revealed significant differences between January/February and August/September. Similarly, a comparison by gender showed a significant difference ( = 0.028). However, there were no significant differences between osteoporosis-associated and non-osteoporosis-associated fractures.

Conclusions: The majority of patients did not achieve sufficient vitamin D levels through endogenous synthesis and substitution did not lead to toxic levels. This suggests that substitution is reasonable and safe even during the summer months.