High Bone Mass in a Female Hutterite Population

We examined a Hutterite population (n = 243) to determine if their agriculturally diverse, self-sufficient communal lifestyle promotes optimal bone mass attainment because of adequate calcium intake and high physical activity levels during growth and young adulthood. We measured total body (TB) and lumbar bone mineral content (BMC) and bone mineral density (BMD) in 39 school-age (younger) females and 204 working (older) females. Forty-five percent of older females and 79% of younger females currently consumed > or = 3 servings (svg) of dairy per day. Older females had lumbar (0.6 +/- 1.3) and TB (1.1 +/- 1.1) BMD Z scores greater than 0 (both, p < 0.001). The lumbar BMD Z score of younger females was not different from 0 (-0.1 +/- 1.0; p = 0.5). Both lumbar (r = 0.46; p < 0.001) and TB (r = 0.20; p = 0.02) BMD Z scores increased with increasing age. In multiple regression analyses for older females, lumbar bone area (p < 0.001), weight (p < 0.001), current hours on feet per day (p = 0.01), colony workload (p < 0.01), and estrogen status (p = 0.06) predicted lumbar BMC. TB bone area (p < 0.001), current hours on feet per day (p < 0.001), and colony workload (p < 0.01) predicted TB BMC. For younger females, lumbar bone area (p < 0.001), weight (p < 0.01), years in present colony (p = 0.02), and menses (p < 0.001) predicted lumbar BMC. TB bone area (p < 0.001), height (p < 0.01), years in present colony (p = 0.03), and menses (p < 0.01) predicted TB BMC. The effect of colony workload could not be separated from other factors different by colony. A heritability estimate of 0.66 was calculated for lumbar BMD using mother and daughter Z scores. Adequate calcium intake during growth, high physical activity early in life, and genetic factors may be contributing to above normal BMD levels in adult female Hutterites.