DIETARY CAFFEINE INTAKE IS NOT CORRELATED WITH ADOLESCENT BONE GAIN

Objective: This study was conducted to determine whether dietary caffe ine consumed by American white females between ages 12 to 18 affects t otal body bone mineral gain during ages 12 to 18 or affects hip bone d ensity measured at age 18. Methods: The Penn State Young Women's Healt h Study is a longitudinal investigation of bone, endocrine and cardiov ascular health in non-Hispanic, white, teenage women. Nutrient and foo d group intakes were obtained by averaging over 6 years of prospective diet records. The cohort, as of age 18, (n = 81) was separated into t hree subgroups according to mean daily caffeine intake averaged across ages 12 to 18. Group I (n = 37) consumed less than 25 mg caffeine per day; Group II (n = 33) consumed 25 to 50 mg caffeine per day; and Gro up III (n = 11) consumed greater than 50 mg caffeine per day. The grou p mean daily caffeine intakes (SD) were Group I = 14 (6) mg/day; Group II = 35 (7) mg/day; Group III = 77 (27) mg/day. Total body bone gain and hip bone density were determined by dual energy x-ray absorptiomet ry (DXA). Results: There were no significant differences among the thr ee caffeine intake groups for total body bone mineral gain during the ages 12 to 18 or of hip bone density at age 18. The low caffeine intak e group consumed more milk (and therefore more calcium) and more fruit per day than did the other two groups. Group III, the highest caffein e intake group, consumed more sugar per day than did the other two gro ups. The observed differences in nutrient and food intakes among the t hree groups were not associated with any differences in anthropometric measurements or bone gain among the three groups. Conclusion: These f indings indicate that dietary caffeine intake at levels presently cons umed by American white, teenage women is not correlated with adolescen t total bone mineral gain or hip bone density at age 18.