Objective: To describe the association of lifetime intake of caffeinated coffee, in cup-years, to bone mineral density (BMD) of the hip and spine in postmenopausal women; and to determine the effect of regular milk intake on this association.
Design: Women from an established epidemiologic cohort had measures of BMD and gave a medical and behavioral history that included caffeinated coffee and daily milk intake between the ages of 12 and 18 years, 20 and 50 years, and 50 years of age and older.
Setting: A community-based population of older women, Rancho Bernardo, Calif.
Participants: All 980 postmenopausal women aged 50 to 98 years (mean age, 72.7 years) who participated between 1988 and 1991.
Main outcome measures: Bone density at the hip and lumbar spine measured by dual energy x-ray absorptiometry.
Main results: There was a statistically significant graded association between increasing lifetime intake of caffeinated coffee and decreasing BMD at both the hip and spine, independent of age, obesity, parity, years since menopause, and the use of tobacco, alcohol, estrogen, thiazides, and calcium supplements. Bone density did not vary by lifetime coffee intake in women who reported drinking at least one glass of milk per day during most of their adult lives.
Conclusions: Lifetime caffeinated coffee intake equivalent to two cups per day is associated with decreased bone density in older women who do not drink milk on a daily basis.