Diabetes mellitus prevalence is increasing in South Asians but is stable in Chinese living in Singapore and Mauritius.

BACKGROUND: Asia is experiencing a type 2 diabetes epidemic, but prevalence differs by ethnicity and level of socioeconomic development. Singapore and Mauritius have implemented comprehensive campaigns to address this public health problem. We compared diabetes and obesity prevalence trends among Chinese and South Asians living in Singapore and Mauritius to determine the contribution of ethnicity and economic development to diabetes. METHODS: Age-specific data from serial national population-based surveys in Singapore and Mauritius between 1987 and 2010 were used to estimate age-standardized diabetes and obesity prevalence. Modified Breslow-Cox proportional hazard models were used to obtain rate ratios for diabetes risk factors. RESULTS: In Singapore, the age-standardized prevalence of diabetes remained stable for Chinese (men: 14% in 1992, 13% in 2010; women: 12% in 1992, 10% in 2010), but increases were observed for South Asians (men: 20% in 1992, 26% in 2010; women: 18% in 1992, 20% in 2010). There were similar patterns in Mauritius. In both countries, obesity prevalence trends were stable for Chinese women, but increased for Chinese men and South Asians. Associations between obesity and diabetes were stronger in Chinese than South Asians regardless of country. CONCLUSIONS: Despite different socioeconomic settings in Singapore and Mauritius, we observed rising diabetes prevalence among South Asians but stable prevalence in Chinese in both countries. This provides further evidence that ethnicity contributes to the development of diabetes, and that there should be an increased emphasis on future prevention strategies targeting South Asian populations in these countries.

The validity of self-reported cancer in an Australian population study.

OBJECTIVE: The aim of this study is to determine the validity of self-reported cancer data by comparing it to the Australian Cancer Database (ACD). METHODS: Self-reported data were obtained from the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, which were then linked to the ACD up until 31 December 2010. Positive predictive value, negative predictive value, sensitivity and specificity were calculated. Cohen's kappa coefficient (ĸ) was also calculated to assess the agreement between self-reported cancer and the ACD. Logistic regression was used to examine the determinants associated with false negative and false positive reporting. RESULTS: The overall sensitivity of self-report cancer was 71.1%, and sensitivities showed great variation by cancer site. Higher sensitivities were observed for breast (90.7%), bowel (77.8%) and prostate (77.1%) cancers, whereas the lowest sensitivity was observed for melanoma of the skin (36.9%). Similarly, the kappa coefficient analysis showed substantial agreement for self-reported breast cancer (ĸ=0.79) and moderate agreement for melanoma (ĸ=0.45) against the ACD. Years since cancer diagnosis and older age were associated with false negative reporting and older age was associated with false positive reporting. CONCLUSIONS AND IMPLICATIONS: The use of self-reported cancer to collect cancer outcomes has varying reliability, depending on cancer type and population. The findings presented here may assist medical researchers in making informed decisions when conducting research using self-reported cancer data in Australia where the acquisition of registry data is not feasible.