Familial correlation of bone mineral density, birth data and lifestyle factors among adolescent daughters, mothers and grandmothers.

This study aimed to clarify the relationship between skeletal or lifestyle factors among Japanese daughter-mother, mother-grandmother and daughter-grandmother pairs. We performed a cross-sectional study in a cohort of Japanese adolescent daughters (12-18 years of age), their mothers (339 pairs) and grandmothers on their mothers' side (34 pairs). Gestational age, birth weight, age at menarche and presence of menarche or menopause were surveyed in the participants. Height, body weight and lumbar 2-4 bone mineral density (BMD) were measured. Dietary intake and current physical activity were assessed by using questionnaires. Gestational age and age at menarche were significantly correlated among daughters, mothers and grandmothers (P < 0.001). BMD was significantly correlated between daughters and mothers (P < 0.001), while it was not significantly correlated between daughters and grandmothers or between mothers and grandmothers. Dietary intake of calcium and vitamin D, and the frequency, duration and intensity of current physical activity were significantly correlated between daughters and mothers (P < 0.05), although no significant correlation was found between daughters and grandmothers, or between mothers and grandmothers. The parameters for exercise indicated a positive correlation for BMD in the daughters and the mothers, but not in the grandmothers. The results suggested that estrogen deficiency decreases familial correlation for BMD after menopause. Achieving high BMD through exercise may be important for prevention of postmenopausal osteoporosis in premenopausal low-height mothers.