Author(s): HORIUCHI, Y., HORIUCHI, M., Institution: KYUSHU SANGYO UNIVERSITY, Country: JAPAN, Abstract-ID: 1301

INTRODUCTION:

Approximately 90% of peak bone mass is attained by the end of the second decade of life, making childhood and adolescence critical periods for skeletal development [1]. Although bone mineral accrual is influenced by multiple factors, milk consumption has received considerable attention, with inconsistent findings reported [2]. Few studies have distinguished the effects of milk intake during specific developmental stages (pre-pubertal, pubertal, and late adolescence) on bone mineral density (BMD) in young adulthood or examined potential sex differences. Therefore, this study investigated associations between self-reported milk consumption during three developmental stages (6-12,, 12–15, and 15–18 years) and current BMD in university students. We hypothesized that greater milk intake, particularly during puberty, would be associated with higher BMD.

METHODS:
A total of 183 university students (males n=92; females n=91) participated. Height, body mass, and body fat percentage were assessed using bioelectrical impedance, and BMI was calculated. Milk intake during childhood and adolescence was evaluated via questionnaire [3]. BMD was assessed using quantitative ultrasound (AOS-100, Aloka, Japan). The osteo sono-assessment index (OSI), calculated from transmission index and squared speed of sound, was used as a proxy for BMD [4].

RESULTS:
Age and BMI were similar between sexes (P>0.05). Males had greater height and body mass, whereas females had higher body fat percentage (all P<0.001). OSI was higher in males (3.348±0.379) than females (3.135±0.433; P<0.001).
A significant interaction between sex and milk intake during the pre-pubertal period (6–12 years) was observed. Participants consuming ≥1 cup/day showed higher OSI compared with those consuming <1 cup/day in both sexes, suggesting a beneficial effect of milk intake during early development. In contrast, OSI was not associated with milk intake during later periods (12–18 years and ≥18 years). Positive correlations between OSI and body mass and BMI were observed in females only.

CONCLUSION:
Milk intake during the pre-pubertal period appears more strongly associated with higher BMD in young adulthood than intake during later adolescence. Additionally, lower body mass may be a risk factor for reduced bone status in females.

References
[1] Weaver CM et al. (2016) Osteoporos Int, 27(4):1281–1386.
[2] Hong et al. (2013) Nutr Res Pract, 7(5):409-17.
[3] Kalkwarf et al. (2003) Am J Clin Nutr, 77(1):257-65.
[4] Hamanaka et al. (1999) J Bone Miner Metab, 17(3):195-200.