T. Lloyd et al., DIETARY CAFFEINE INTAKE IS NOT CORRELATED WITH ADOLESCENT BONE GAIN, Journal of the American College of Nutrition, 17(5), 1998, pp. 454-457
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.