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

Objectives-To study the effects of historical milk consumption on current bone mineral density at the hip and spine. Design-Cross sectional study. Subjects-284 community based women aged 4474 years recruited from four general practice age-sex registers in Cambridge. Subjects categorised their average milk consumption up to age 25, from age 2544, and 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 energy 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 significant independent predictor of bone mineral density at all sites in multiple 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 effects of milk consumption from age 25-44 and from age 44 to the present were similar in direction though not statistically significant. Conclusion-Frequent milk consumption before age 25 favourably influences hip bone mass in middle aged and older women.