Background: Decreased bone mineral density (BMD) has been linked to metabolic disorders, such as type 2 diabetes. However, results regarding the metabolic syndrome (MetS), a cluster of at least 3 of 5 cardiovascular risk parameters with potentially contradictory effects on BMD are still inconclusive. Objective: We investigated the effect of MetS and its single parameters on BMD at 3 sites in community-dwelling older subjects. Methods: 1,402 subjects (51.1% female, 68 ± 4 years old) from the Berlin Aging Study II (BASE-II) were included. MetS was defined as suggested by IDF/NHLBI/AHA. Insulin resistance (IR) was assessed by the homeostasis model of IR. BMD (lumbar spine, femur neck, hip) and trunk fat were measured by dual-energy X-ray absorptiometry. Osteoporosis was defined by a T score of ≤-2.5. Results: MetS was present in 29.6% of women and 41.7% of men. In regression models, we observed a positive association of MetS with the BMD of the lumbar spine (p = 0.005) and hip (p = 0.028) in women even after adjustment for risk factors, but no effect of the single parameters apart from IR. In contrast, there was no association between MetS and BMD in men. However, higher trunk fat and higher waist circumference were associated with lower levels of BMD in men with or without MetS (p < 0.05). Conclusion: We obtained different results in men and women. In women, the positive though slight effect of MetS on BMD could not be explained by single MetS components apart from IR. In men, central obesity was negatively associated with BMD, suggesting that the metabolic effects driven by visceral fat have a negative impact.

Purpose Age‐related changes affect vitamin D absorption and metabolism. Low 25‐hydroxyvitamin D concentrations have been reported as risk factor for the development of metabolic syndrome (MetS). However, recent evaluations suggest this association might be explained by obesity or insulin resistance (IR) in subjects with MetS. Our aim was to analyze associations between vitamin D insufficiency and MetS in a young cohort without diabetes and two senior cohorts with and without diabetes. Methods Four hundred sixteen young and 1357 older BASE‐II participants were analyzed. Type 2 diabetes (T2D) was defined according to European Society of Cardiology (ESC) guidelines, MetS as suggested by International Diabetes Federation/American Heart Association/National Heart, Lung and Blood Institute (IDF/AHA/NHLBI 2009). Vitamin D insufficiency was defined as 25‐hydroxyvitamin D concentrations <50 nmol/L. Among other confounders, BMI and IR were taken into account. Results MetS was prevalent in 7.7% of the young and in 35.6% of the older BASE‐II participants and T2D occurred in 12.7% of the older participants. In young subjects without diabetes, vitamin D insufficiency was associated with an independent 3.2‐fold increased odds of having MetS (OR: 3.2 CI: 1.0–8.7; p = 0.042). However, in the older participants, this association was lost once BMI was taken into account among those with diabetes, and once IR was taken into account among those without diabetes. Conclusion Independent associations between vitamin D insufficiency and MetS were only found among young subjects without diabetes. In the older adults, BMI annihilated these associations among subjects without diabetes as did HOMA‐IR among subjects with diabetes.