ISSN:
1433-2965
Keywords:
Body mass index
;
Bone density (areal)
;
Bone mineral content
;
Calcium intake
;
Gynecologic age
;
Physical activity (exercise)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The determinants of bone mass, i.e., size and density, in young adult women after cessation of growth in length of the bones are not well understood. Usual dietary calcium (Ca) intakes and physical activity (PA) patterns during the post-pubertal half-decade have been considered as two important factors contributing to bone mass. In the present hypothesis-generating cross-sectional study, radial bone mineral content and density were measured by single-photon absorptiometry at two sites containing different proportions of trabecular and cortical bone tissue in 705 healthy, Caucasian college women (18–22 years). Ca intake during high school and college, as estimated by milk and cheese intake only, was categorized into low, moderate and high groups; and physical activity, estimated during the same time frame, was also categorized into low, moderate and high groups. Bone measurements were related to both long-term dietary Ca intake from milk and cheese and long-term PA in sports, dance or other exercises, as assessed by recall. By univariate analyses, both distal and mid-radial bone mineral content (BMC) and areal bone mineral density (BMD) were found to be positively related to gynecological age (GA) (p〈0.01). Also, independent effects of long-term Ca intake (p〈0.05) on distal BMC and BMD, and of long-term PA (p〈0.05) on distal and mid-BMC and BMD were observed. When adjusted for GA, body mass index (BMI) and PA, the relationship between long-term Ca no longer remained significant; but when we adjusted for GA, BMI and long-term Ca, the significance of PA on radial bone remained essentially unchanged. The combined effects of both long-term moderate Ca and long-term moderate PA versus long-term low Ca and long-term low PA in college-age women showed that distal radial bone parameters were significantly greater in the moderate/moderate individuals when compared with subjects with low levels of both variables. The high/high combination also significantly improved distal bone variables, but in general not much more so than the moderate/moderate pair. Mid-radial bone values showed only statistical trends, when analyzing high/high versus low/low comparisons. We conclude that adequate levels (moderate or high of either) of both Ca and PA during adolescence and early adulthood are positive and independent determinants of both radial BMC and BMD, including much trabecular bone tissue, but that long-term exercise exerts a greater overall beneficial effect on distal radial bone measurements than does long-term Ca consumption.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01624147
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