Incidence and risk factors for type 2 diabetes mellitus in transitional Thailand: results from the Thai cohort study

Abstract

Background: Type 2 diabetes mellitus (T2DM) is increasingly prevalent in countries undergoing rapid development, including Thailand. We assessed T2DM incidence over an 8-year period in a nationwide cohort of Thai adults.

Methods: Thai Cohort Study participants were surveyed in 2005, 2009 and 2013. The analysed cohort members were aged (15-88), did not have diabetes in 2005 and were followed up by questionnaire in 2013 (n=39 507). T2DM was ascertained using self-report, which has been validated using physician interviews. We calculated the 8-year cumulative incidence of T2DM. Multivariable logistic regression assessed associations between potential risk factors and T2DM incidence.

Results: 8-year cumulative incidence of T2DM (2005 to 2013) was 177 per 10 000 (95% CI 164 to 190). Crude and age-standardised cumulative incidences of T2DM by sex were 249 per 10 000 (95% CI 226 to 272) and 222 per 10 000 (95% CI 219 to 225) for men; and 119 per 10 000 (95% CI 105 to 133) and 96 per 10 000 (95% CI 94 to 98) for women, respectively. T2DM increased significantly for both sexes with increasing age and body mass index (BMI) (p trend <0.001 for both). Residence in an urban area as a child associated with T2DM among men and women (OR=1.4, 95% CI 1.1 to 1.7 and OR=1.4, 95% CI 1.01 to 1.79); this was no longer statistically significant after adjusting for BMI. Among men, smoking (OR=1.7, 95% CI 1.3 to 2.2) and alcohol intake (OR=1.8, 95% CI 1.1 to 3.0) were associated with T2DM.

Conclusions: This study found that the sociodemographic and lifestyle changes that have accompanied Thailand's economic development are associated with T2DM risk in a large cohort of Thai adults. Our findings highlight the need to address these transitions to prevent a further increase in the national incidence of T2DM, particularly among Thai men.

Keywords: EPIDEMIOLOGY; PUBLIC HEALTH.

Figure 1

Selection of study participants from the Thai Cohort Study. *Participants were selected based on self-reported diabetes status in 2005 and available follow-up data in 2009 and 2013. The self-reported positives in 2005 were excluded (n=902) as were those missing in 2009 and those with a missing diabetes status in their questionnaires. Eight-year cumulative incidence was calculated with the 39 507 remaining participants in 2013.

Figure 2

Cumulative incidence of T2DM between 2005 and 2013 by age and sex.

Figure 3

Sensitivity analysis comparing the ORs for incidence of diabetes between 2005 and 2009 according to diabetes reporting pattern in 2009 and 2013. Models were run for 4-year cumulative incidence between 2005 and 2009 among men, including the following participants. (A) Including all male participants followed up in 2009 (n=26 885). (B) Excluding the 107 male participants who reported having incident diabetes in 2009 but subsequently reported not having diabetes in 2013 (n=26 778). (C) Excluding the 7949 male participants who were lost to follow-up in 2013 (n=18 936). (D) Excluding the 7949 male participants who were lost to follow-up in 2013 and the 107 male participants who reported having incident diabetes in 2009 but subsequently reported not having diabetes in 2013 (n=18 829).