Differences in health characteristics between native Japanese and Japanese-Americans

Osteoporosis and Fracture Risk among Older US Asian Adults

PURPOSE OF REVIEW

This review summarizes the current knowledge regarding osteoporosis and fracture among older US Asian adults.

RECENT FINDINGS

Asian adults have lower (areal) bone density than non-Hispanic White adults and thus are more likely to be diagnosed and treated for osteoporosis, despite their lower risk of hip fracture. The latter may relate to favorable characteristics in hip geometry, volumetric bone density, and bone microarchitecture; lower risk of falls; and other clinical factors. The fracture risk calculator FRAX accounts for the lower risk of hip fracture among US Asian adults. However, data on major osteoporotic fracture risk remain limited. Fracture rates also vary by Asian subgroup, which may have implications for fracture risk assessment. Furthermore, among women receiving bisphosphonate drugs, Asian race is a risk factor for atypical femur fracture, an uncommon complication associated with treatment duration. Recent clinical trial efficacy data pertaining to lower bisphosphonate doses and longer dosing intervals may be relevant for Asian adults. More research is needed to inform osteoporosis care of US Asian adults, including risk-benefit considerations and the optimal duration of bisphosphonate treatment. Greater evidence-based guidance for primary fracture prevention among US Asian adults will ensure health equity in the prevention of osteoporotic fractures.

Genetic and environmental influences on height from infancy to early adulthood: An individual-based pooled analysis of 45 twin cohorts

Height variation is known to be determined by both genetic and environmental factors, but a systematic description of how their influences differ by sex, age and global regions is lacking. We conducted an individual-based pooled analysis of 45 twin cohorts from 20 countries, including 180,520 paired measurements at ages 1-19 years. The proportion of height variation explained by shared environmental factors was greatest in early childhood, but these effects remained present until early adulthood. Accordingly, the relative genetic contribution increased with age and was greatest in adolescence (up to 0.83 in boys and 0.76 in girls). Comparing geographic-cultural regions (Europe, North-America and Australia, and East-Asia), genetic variance was greatest in North-America and Australia and lowest in East-Asia, but the relative proportion of genetic variation was roughly similar across these regions. Our findings provide further insights into height variation during childhood and adolescence in populations representing different ethnicities and exposed to different environments.

Height, weight, menstrual and reproductive factors and risk of gastric cancer among Japanese postmenopausal women: analysis by subsite and histologic subtype

To clarify whether reproductive factors have an impact on gastric cancer in Japanese females, a case-control study was conducted using data from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC), Japan. The study subjects included 365 postmenopausal women with gastric cancer and 1,825 age-class frequency-matched noncancer outpatients presenting at Aichi Cancer Center in 1988-1998. Cases were further divided with regard to the anatomic subsite (upper third, middle third, lower third) and histologic subtypes (differentiated, nondifferentiated) and the association was evaluated using odds ratios (ORs) estimated by the logistic regression model, adjusting for potential confounding factors. A high body weight and corresponding body mass index at age 20 moderately increased the risk of gastric cancer, especially for middle third and nondifferentiated cancers. Risk fluctuation with early or late age at menarche and menopause and total duration of fertility was not consistent. Individuals with a high age at first parity tended to show decreased risk of cancer, irrespective of their subsite or histologic subtype. The ORs were decreased with a short average period of breastfeeding, especially for upper third and nondifferentiated cancers. From these results, however, it appears that height, weight, menstrual and reproductive factors have less impact on gastric cancer than environmental factors such as smoking and dietary habits or family history of gastric cancer.