Age-related Bone Mineral Density Trends in Sri Lankan Adults: Defining Population-specific Reference Values

Abstract

Background: Absence of normative bone mineral density (BMD) data for Sri Lankans has led to reliance on Caucasian references, misestimating BMD in this population. Objectives: To establish age-related BMD trends in Sri Lankans for optimal bone health management Methods: This retrospective, correlational study analysed data from 11,925 patients (4,549 men, 7,376 women) aged 20-80 years, who underwent lumbar and hip scans during health check-ups at five private institutions in Western Province (2015-2024). Subjects with affecting bone metabolism were excluded. BMD measurements obtained using Hologic DXA scanners, demographic, clinical data collected via standardised questionnaire. Subjects grouped by decade to maintain consistency with Caucasian references. Results: For males, mean lumbar BMD values (g/cm²) across age groups were 1.004 (21-30 years), 1.019 (31-40 years), 1.004 (41-50 years), 0.979 (51-60 years), 0.993 (61-70 years), and 0.995 (71-80 years). For women, values were 0.974, 0.982, 0.978, 0.874, 0.805, and 0.786 g/cm². Compared to Caucasians, Sri Lankan BMD values were significantly lower, except in elderly men and peri/post-menopausal women’s hip. Peak lumbar total BMD observed in 31-40 years. The greatest decline in spinal BMD occurred between the fifth and sixth decades, with a reduction of 10.4% per decade in women and, it was 2.5% per decade in men. Statistically significant difference in BMD was observed between males and females, across all regions (p<0.05). Spinal BMD was correlated positively with weight (r=0.47) (p<0.05) and height (r=0.39) (p<0.05). In postmenopausal women, spine and hip BMD were negatively correlated with years since menopause. Among women, strongest correlation between weight and hip BMD occurred in 41-50 years. Nonlinear cubic regression model demonstrated better fit than the linear model. Conclusion: These findings establish normative BMD values for Sri Lankans, highlighting age- related trends and differences from Caucasians. Future research should include all provinces for broader applicability.