Wrist, spine, and hip bone density in women with variable histories of lactation.

This study investigated the relationship between long-term lactation (greater than or equal to 10 m/child) and bone density in women aged 26-37. The subjects either experienced long-term lactation for 1-2 children (n = 10), long-term lactation for 3-4 children (n = 8), or were nulliparous (n = 10). The three groups did not differ significantly in height, weight, percent of ideal weight, usual caffeine and calcium intake, or duration of oral contraceptive use. Bone-density measurements were obtained by single- or dual-photon absorptiometry from the ultradistal radius, lumbar spine (L2-L3), and three hip sites: femoral neck, Ward's triangle, and trochanteric. Lactation history was not associated with significant differences in bone density in any bone site. With respect to height, weight, Ca intake, and duration of lactation, only height was correlated to bone density and only for L2-L3 (r = 0.48, p less than 0.02). Thus, a history of long-term lactation may not be associated with low peak adult bone density.