Milk consumption throughout life and bone mineral content and density in elderly men and women.
Association between bone mineral density and bone mineral content in old age and milk consumption in adolescence, midlife, and old age was assessed. The association was strongest for milk consumption in midlife: those drinking milk daily or more often had higher bone mineral density and content in old age than those drinking milk seldom or never.


BACKGROUND
The role of lifelong milk consumption for bone mineral density (BMD) and bone mineral content (BMC) in old age is not clear. Here we assess the association between hip BMD and BMC in old age and milk consumption in adolescence, midlife, and current old age.


METHODS
Participants of the Age, Gene/Environment Susceptibility-Reykjavik Study, aged 66-96 years (N = 4,797), reported retrospective milk intake during adolescence and midlife as well as in current old age, using a validated food frequency questionnaire. BMC of femoral neck and trochanteric area was measured by volumetric quantitative computed tomography and BMD obtained. Association was assessed using linear regression models. Differences in BMC, bone volume, and BMD in relation to milk intake were portrayed as gender-specific Z-scores.


RESULTS
Men consuming milk ≥ once/day during midlife had 0.21 higher Z-scores for BMD and 0.18 for BMC in femoral neck (95 % confidence interval 0.05-0.39 and 0.01-0.35, respectively) compared with < once/week. Results were comparable for trochanter. For women the results were similar, with slightly lower differences according to midlife milk consumption. For current and adolescent milk consumption, differences in Z-scores were smaller and only reached statistical significance in the case of BMD for current consumption in men, while this association was less pronounced for BMC.


CONCLUSIONS
Our data suggest that regular milk consumption throughout life, from adolescence to old age, is associated with higher BMC and BMD in old age, with no differences seen in bone volume. The strongest associations are seen for midlife milk consumption in both genders.
Unit for Nutrition Research, University of Iceland and Landspitali, National University Hospital, Reykjavik, Iceland, tinnaey@landspitali.is.
T
T
Eysteinsdottir
T I
TI
Halldorsson
I
I
Thorsdottir
G
G
Sigurdsson
S
S
Sigurðsson
T
T
Harris
L J
LJ
Launer
V
V
Gudnason
I
I
Gunnarsdottir
L
L
Steingrimsdottir
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015519:Bone Density / Q000502:physiology*; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D004032:Diet / Q000706:statistics & numerical data; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005272:Femur Neck / Q000502:physiology; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D008297:Male; D008892:Milk; D012727:Sex Characteristics