The present study was to determine age- and gender-based spinal bone mineral density (BMD) by quantitative computed tomography (QCT) in Thais and to compare it with that of Westerners. Four hundred and twenty five healthy Thais, age 20 to 76 years (322 females, mean age 43.4 years;103 males, mean age 42.8 years) were recruited for BMD assessment by QCT. Spinal BMD peaks in the 20-29 year age group in both genders with a mean value of 171.9 mg/cu cm in females and 171.0 mg/cu cm in males. It subsequently decreases in older age groups. Males’ BMD has a higher rate of decline than females’ until age 40-49. It then stabilizes from 50-59 while females’ BMD shows the highest rate decline at this period. After the mid-50’s, both genders have bone loss from aging. Compared to Westerners, peak bone mass is reached in the same age group in both genders. Peak bone mass of Thai females is significantly higher than Western females, but that of Thai males is not significantly higher than Western males. BMD of Thai males in the 50-59 and over-60 age groups is higher than that of Westerners. The findings suggest that the cut-off points for osteopenia and osteoporosis,in Thai females are at spinal BMD lower than 143.6 mg/ cu cm and 101.15 mg/cu cm, respectively. While the values lie at 143.2 mg/cu cm and 101.5 mg/cu cm among Thai males for osteopenia and osteoporosis, respectively.

Keywords: Quantitative computed tomography (QCT), Bone mineral density (BMD)