Prevalence of Diabetes and Prediabetes in 15 States of India: Insights from the ICMR - INDIAB Population-Based Study

Background

The current estimates of diabetes prevalence obtained from various regions of India do not accurately reflect the disease burden of the country. This is attributed to the diversity of Indian geography and heterogeneous nature of Asian Indian population. Moreover, there is no uniformity in methods and sampling designs employed to calculate the national estimate of diabetes in existing studies.

Aim

The ongoing national Indian Council of Medical Research–INdia DIABetes (ICMR-INDIAB) study aimed at estimating the national prevalence of diabetes and prediabetes across India.

Study Population Profile

• Adult (aged ≥20 years) urban and rural residents from 14 states and one union territory in India
• Total study population: 57117 (16909 urban and 40208 rural)

Method

Study Design

Ongoing cross-sectional, multistage, community-based survey

Phases of the Trial

Phase 1

• Four regions representing: South (Tamil Nadu), North (Chandigarh), East (Jharkhand) and West (Maharashtra).
• Study period: November 17, 2008 to April 16, 2010

Phase 2

• Five mainland states: Andhra Pradesh, Bihar, Gujarat, Karnataka, and Punjab.
• Study Period: September 24, 2012 to July 26, 2013

Phase 3

• Six north-eastern states (Assam, Mizoram, Arunachal Pradesh, Tripura, Manipur, and Meghalaya.
• Study period: January 5, 2012 to July 3, 2015

Assessments

• Each study participant was administered a detailed questionnaire to collect information about demographic and socioeconomic parameters and behavioural factors.
• Fasting blood glucose (FBG) and 2-hour post-load glucose (after an oral glucose tolerance test) were determined; both tests were capillary blood glucose measurements.
• The prevalence of diabetes in different states was assessed in relation to socioeconomic status (SES) of individuals and the per-capita gross domestic product (GDP) of each state.
• Multiple logistic regression analysis was used to determine the association of various factors with the prevalence of diabetes and prediabetes.

Results

• The cumulative data from 15 states included in the study represented a total adult population of 363·7 million people i.e. 51% of India’s adult population.
• The overall prevalence of diabetes (as per the WHO criteria) in all 15 states of India was 7·3%, with lowest prevalence recorded in Bihar (4·3%) and highest prevalence recorded in Punjab (10·0%). The prevalence of diabetes was almost two-fold higher in urban areas vs. rural areas (11·2% vs. 5·2%; p<0·0001). Diabetes prevalence was also higher in mainland states vs. the northeast states (8·3% vs. 5·9%; p<0·0001).
• Men in urban areas had an odds ratio (OR) for diabetes of 1·84 and women in urban areas had an OR of 1·58 as compared to their rural counterparts, after adjusting for age, BMI, systolic blood pressure, SES, and smoking status.
• The age group after which the prevalence of diabetes took off was 25-34 years in both urban and rural areas. The prevalence of diabetes peaked at the age group of 55-64 years.
• Around 47.3% individuals (1862/3938) identified as having diabetes had not been diagnosed previously (42% in urban areas vs. 53% in rural areas; 46% in mainland states vs. 49% in north-east states).
• In the rural population, prevalence of diabetes was higher among individuals in the higher SES categories in both the mainland and northeast states.
• In urban areas (Chandigarh, Andhra Pradesh, Tamil Nadu, Maharashtra, and Punjab in the mainland and Tripura, Manipur and Assam in the northeast), diabetes was more prevalent among individuals of low SES vs. those with higher SES.
• A higher prevalence of diabetes was evident in states with higher per-capita GDP. Chandigarh with highest per-capita income amongst the 15 states had highest prevalence of diabetes (13.6%) and Bihar with the lowest per-capita income had the lowest prevalence of diabetes (4.3%).
• The overall prevalence of prediabetes in the included 15 states was 10·3% as per the WHO criteria and 24.7% as per the ADA criteria. Highest prevalence was recorded in Tripura (14.7%) and lowest prevalence was recorded in Mizoram (6%). In general, the prevalence of impaired fasting glucose was more than twice higher than that of impaired glucose tolerance.
• A substantially lower diabetes-to-prediabetes ratio was evident in the northeast (1:1·8) than in the mainland states (1:1·2). The ratio was also lower in rural (1:1·9) vs. urban areas (1:1).
• Age, male gender, obesity, hypertension, and family history of diabetes were identified as independent risk factors for diabetes in both urban and rural areas (Table 1).

Conclusion

• The prevalence of diabetes varied widely between 15 states of India that were included in the analysis.
• The epidemic of diabetes in India seems to be in a state of transition with low SES groups in the urban areas of the more economically developed states being prominently affected.
• Prevalence and spread of diabetes in economically disadvantaged sectors of the country is a matter of concern that needs to be addressed urgently with effective preventive strategies.
• The prevalence of prediabetes exceeded that of diabetes in most of the country, except in some of the economically progressed states, where the diabetes-to-prediabetes ratio has equalised or even reversed. The diminution of the prediabetes pool increases the possibility of stabilisation of diabetes prevalence in the near future in these states.

Lancet Diabetes Endocrinol. 2017 (Published Online); http://dx.doi.org/10.1016/S2213-8587(17)30174-2