DESIGN: Population-based incidence study using data from a medical savings fund.
STUDY POPULATION: Chinese, Malay, and Indian residents in Singapore.
METHODS: Data on all cataract operations performed for "senile cataract" (International Classification of Diseases, Ninth Revision, Clinical Modification code 366.1) between 1991 and 1996 were retrieved from Medisave, a population-wide, government-administered medical savings fund. The Singapore census was used as a denominator to allow an estimation of age, sex, and race-specific annual rates of cataract surgery.
RESULTS: Between 1991 and 1996, 61 210 cataract operations for "senile cataract" were performed on Singapore residents, which is equivalent to an average rate of 356.4 cataract operations per 100 000 persons per year (95% confidence interval [CI], 353.6-359.2). The average rate was highest for Indians (age-sex adjusted rate of 396.5 per 100 000/year), followed by Chinese (371.2 per 100 000/year), and lowest for Malays (237.2 per 100 000/year). Women had higher rates of cataract extraction than men (age-adjusted relative risk, 1.14; 95% CI, 1.11-1.17), with this pattern consistent across the 3 racial groups. The rate of cataract extraction increased by an average of 40 operations per 100 000/year (95% CI, 28.6-52.8) between 1991 and 1996. Overall, the proportion of cataract extraction without concurrent intraocular lens implantation was low (n = 762, 1.2%), but rates still decreased by an average of 0.8 per 100 000 per year (95% CI, 0.03-1.5) during the 6 years.
CONCLUSIONS: The rate of cataract extraction in Singapore is consistent with rates seen in developed countries in the West. Racial variation in rates suggests varying predisposition to cataract development and/or threshold for cataract surgery between Chinese, Malay, and Indian populations in Singapore.
PURPOSE: Information regarding mediators of differences in bone mineral density (BMD) among Asian ethnicities are limited. Since the majority of hip fractures are predicted to be from Asia, differences in BMD in Asian ethnicities require further exploration. We compared BMD among the Chinese, Malay, or Indian ethnicities in Singapore, aiming to identify potential mediators for the observed differences.
METHODS: BMD of 1201 women aged 45-69 years was measured by dual-energy X-ray absorptiometry. We examined the associations between ethnicity and BMD at both sites, before and after adjusting for potential mediators measured using standardized questionnaires and validated performance tests.
RESULTS: Chinese women had significantly lower femoral neck BMD than Malay and Indian women. Of the more than 20 variables examined, age, body mass index, and height accounted for almost all the observed ethnic differences in femoral neck BMD between Chinese and Malays. However, Indian women still retained 0.047 g/cm2 (95% CI, 0.024, 0.071) higher femoral neck BMD after adjustment, suggesting that additional factors may contribute to the increased BMD in Indians. Although no crude ethnic differences in lumbar spine BMD were observed, adjusted regression model unmasked ethnic differences, wherein Chinese women had 0.061(95% CI, - 0.095, 0.026) and 0.065 (95% CI, - 0.091, 0.038) g/cm2 higher lumbar spine BMD compared to Malay and Indian women, respectively.
CONCLUSION: BMD in middle-aged Asian women differ by ethnicity and site. Particular attention should be paid to underweight women of Chinese ethnic origin, who may be at highest risk of osteoporosis at the femoral neck and hence hip fractures.