MILK CONSUMPTION AND BONE-MINERAL DENSITY IN MIDDLE-AGED AND ELDERLY WOMEN

Objectives-To study the effects of historical milk consumption on curr ent bone mineral density at the hip and spine. Design-Cross sectional study. Subjects-284 community based women aged 4474 years recruited fr om four general practice age-sex registers in Cambridge. Subjects cate gorised their average milk consumption up to age 25, from age 2544, an d from age 44 to the present time as greater-than-or-equal-to 1 glass/ day, < 1 glass/day but > 1 glass/week, or < 1 glass/week. Main outcome measures-Bone mineral density at the hip and spine measured by dual e nergy x ray absorptiometry. Results-Data on milk consumption up to age 25 years were available for 252 women. There was a consistent upward trend in bone mineral density at all sites with increasing historical milk consumption (total hip, femoral neck, trochanter, intertrochanter , P<0.05: Ward's triangle, P=0.005). Adjustment for age and body size did not alter these trends. Milk consumption up to age 25 was a signif icant independent predictor of bone mineral density at all sites in mu ltiple linear regression analyses controlling for age, body mass index , menopausal status, smoking, ever use of hormone replacement therapy or oral contraceptives, physical activity, and alcohol intake. The eff ects of milk consumption from age 25-44 and from age 44 to the present were similar in direction though not statistically significant. Concl usion-Frequent milk consumption before age 25 favourably influences hi p bone mass in middle aged and older women.