The effects of lifestyle, dietary dairy intake and diabetes on bone density and vertebral deformity prevalence: The EVOS study

The risk of low and moderate energy fracture is related to bone mineral den sity (BMD). Yet it is uncertain whether the epidemiologic determinants of f racture risk are the same as for low bone density. The European Vertebral O steoporosis Study was a population-based prevalence study of vertebral defo rmity in 36 age-stratified population samples aged 50-80 years. In nearly 4 000 subjects (13 centers), BMD, measurements were also made at the spine, f emoral neck and femoral trochanter. To investigate whether effects of repor ted physical activity on spine deformity risk were mediated through BMD, we modeled these and other risk factor data with BMD as the dependent variate after adjusting for age, center, sex and body mass index (BMI). The signif icant determinants of vertebral deformity risk were also entered into logis tic models of deformity risk that included BMD measurements as covariates. Both current and lifetime physical activity were positively associated with BMD. This effect was stronger with hip BMD than with spine BMD. Lifetime s moking exposure was associated with reduced BMD. Type 2 diabetes mellitus w as associated with increased BMD. Weak positive associations were found bet ween consumption of dairy products and BMD at the three measured sites and these were strengthened by an interaction with measures of physical activit y in men. Physical activity in women had the largest beneficial effect in l ean women and in women exposed to hormone replacement therapy. When fractur e risk was modeled with BMD as a covariate, the lifestyle and dietary deter minants became less strongly related to vertebral deformity risk, suggestin g that BMD may have acted as an intermediary variable. However, heavy physi cal activity in men still increased spine deformity risk after adjusting fo r BMD. It is concluded that physical activity in both genders and milk cons umption in young women might protect against vertebral deformities in later life through their effects on bone density. The adverse effect of smoking on BMD was confirmed. Heavy physical activity in men might increase spine d eformity risk even when BMD is normal.