In the Journals

Higher diabetes rate in low-income countries not fully attributable to risk factors

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March 29, 2016

Diabetes prevalence is higher in low-income vs. middle- or high-income countries, and this disparity cannot be fully explained by conventional risk factors, according to results from the PURE study.

BMI and family history of diabetes were differently related to diabetes prevalence in countries with different income levels, according to researchers.

Gilles R. Dagenais, MD, professor at Institut universitaire de cardiologie et pneumologie de Québec – Université Laval, and colleagues evaluated data from 119,666 adults from four low-income countries (LICs; Bangladesh, India, Pakistan and Zimbabwe), three lower-middle income countries and one occupied territory (LMICs; China, Colombia, Iran and Palestine), seven upper-middle income countries (UMICs; Argentina, Brazil, Chile, Malaysia, Poland, South Africa and Turkey) and three high-income countries (HICs; Canada, Sweden and the United Arab Emirates). At baseline, all participants answered questions regarding diabetes, demographics, ethnicity, family medical history, physical activity, diet, smoking, educational attainment, income and medical history. Participants also underwent blood pressure evaluation, anthropometric measurements, electrocardiography and blood sample collection, and they completed a questionnaire on recent physical activity. Researchers used multivariable analysis to assess correlations between risk factors and diabetes prevalence within the groupings of countries.

Age- and sex-adjusted prevalence of diabetes was highest in LICs (12.3%; 95% CI, 10.9-13.9), followed by UMICs (11.1%; 95% CI, 9.7-12.6) and LMICs (8.7%; 95% CI, 7.9-9.6), and it was lowest in HICs (6.6%; 95% CI, 5.7-7.7; P for trend < .0001).

Multivariable adjusted ORs of risk factors in the overall study population revealed that in all countries, a higher diabetes risk was associated with the following: 5-year increments in                                   age (OR = 1.29; 95% CI, 1.28-1.31), increased waist-to-hip ratio (highest vs. lowest quartile, OR = 3.63; 95% CI, 3.33-3.96), higher BMI (OR = 2.76; 95% CI, 2.52-3.03), male sex (OR = 1.19; 95% CI, 1.13-1.25), residency in an urban area (OR = 1.24; 95% CI, 1.11-1.38), lower educational attainment (OR = 1.1; 95% CI, 1.02-1.19), less physical activity (OR = 1.28; 95% CI, 1.2-1.38); and family history of diabetes (OR = 3.15; 95% CI, 3-3.31). A significant interaction was found between country income grouping and family history of diabetes, BMI and Alternative Health Eating Index (AHEI) score. After adjustment for other risk factors, the ORs of developing diabetes with family history of diabetes were 2.76 in HICs, 2.62 in UMICs, 3.86 in LMICs and 2.86 in LICs (P for trend < .0001). Fully adjusted ORs for diabetes with BMI of at least 35 kg/m2 vs. less than 25 kg/m2 were 2.62 in all country income groups, 5.57 in HICs, 3.12 in UMICs, 1.93 in LMICs and 1.34 in LICs (P for trend < .001). The correlation between AHEI and diabetes was modest in UMICs (1.2) but reversed in LMICs (0.89), whereas no relationship was seen between AHEI and HICs or LICs. Analyses adjusting for age, sex and each additional risk factors revealed a persistent variability in diabetes prevalence in most country income categories, with the highest prevalence seen in LICs (P for trend < .0001).

“Diabetes prevalence was unexpectedly higher in LICs,” the researchers wrote. “The higher rate in LICs is not fully explained by the conventional risk factors. … This suggests that other factors associated with a country’s income level are likely to contribute to the differences in diabetes prevalence.” – by Jennifer Byrne

Disclosure: Dagenais reports no relevant financial disclosures.