Urban rural differences in prevalence of self-reported diabetes in India—The WHO–ICMR Indian NCD...

DIAB-4084; No of Pages 10

Urban rural differences in prevalence of self-reporteddiabetes in India—The WHO–ICMR Indian NCDrisk factor surveillance

Viswanathan Mohan a,*, Prashant Mathur b, Raj Deepa a, Mohan Deepa a,D.K. Shukla b, Geetha R. Menon b, Krishnan Anand c, Nimesh G. Desai d,Prashant P. Joshi e, J. Mahanta f, K.R. Thankappan g, Bela Shah b

aMadras Diabetes Research Foundation & Dr.Mohan’s Diabetes Specialities Centre, 4 Conran Smith Road,

Gopalapuram, Chennai 600 086, IndiabDivision of Noncommunicable Diseases, Indian Council of Medical Research, New Delhi, IndiacCentre for Community Medicine, All India Institute of Medical Sciences, New Delhi, Indiad Institute of Human Behaviour and Applied Sciences, Delhi, IndiaeGovernment Medical Colleges & Hospital, Nagpur, IndiafRegional Medical Research Centre, Dibrugarh, IndiagAchutha Menon Centre for Health Science Studies, Sree Chitra Tirunal Institute for Medical Sciences

and Technology, Trivandrum, India

d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e x x x ( 2 0 0 8 ) x x x – x x x

a r t i c l e i n f o

Article history:

Received 9 March 2007

Accepted 21 November 2007

Keywords:

Self-reported diabetes

Risk factors

India

Surveillance

Urban

Rural

Peri-urban

Non-communicable diseases

Asian Indians

South Asians

a b s t r a c t

Recent reports show strikingly high prevalence of diabetes among urban Asian Indians;

however, there are very few studies comparing urban, peri-urban and rural prevalence rates

of diabetes and their risk factors at the national level. This study is a part of the national non-

communicable diseases (NCD) risk factor surveillance conducted in different geographical

locations (North, South, East, West/Central) in India between April 2003 and March 2005. A

total of 44,523 individuals (age: 15–64 years) inclusive of 15,239 from urban, 15,760 from peri-

urban/slum and 13,524 from rural areas were recruited. Major risk factors were studied

using modified WHO STEPS approach. Diabetes was diagnosed based on self-reported

diabetes diagnosed by a physician. The lowest prevalence of self-reported diabetes was

recorded in rural (3.1%) followed by peri-urban/slum (3.2%) and the highest in urban areas

(7.3%, odds ratio (OR) for urban areas: 2.48, 95% confidence interval (CI): 2.21–2.79, p < 0.001).

Urban residents with abdominal obesity and sedentary activity had the highest prevalence

of self-reported diabetes (11.3%) while rural residents without abdominal obesity perform-

ing vigorous activity had the lowest prevalence (0.7%). In conclusion, this nation-wide NCD

risk factor surveillance study shows that the prevalence of self-reported diabetes is higher in

urban, intermediate in peri-urban and lowest in rural areas. Urban residence, abdominal

obesity and physical inactivity are the risk factors associated with diabetes in this study.

# 2007 Elsevier Ireland Ltd. All rights reserved.

* Corresponding author. Tel.: +91 44 2835 9048; fax: +91 44 2835 0935.E-mail address: [email protected] (V. Mohan).

avai lab le at www.sc iencedi rec t .com

journal homepage: www.e lsev ier .com/ locate /d iabres

URL: http://www.drmohansdiabetes.com

0168-8227/$ – see front matter # 2007 Elsevier Ireland Ltd. All rights reserved.doi:10.1016/j.diabres.2007.11.018

Please cite this article in press as: V. Mohan et al., Urban rural differences in prevalence of self-reported diabetes in India—The WHO–

ICMR Indian NCD risk factor surveillance, Diab. Res. Clin. Pract. (2008), doi:10.1016/j.diabres.2007.11.018

mailto:[email protected]

http://www.drmohansdiabetes.com

http://dx.doi.org/10.1016/j.diabres.2007.11.018



d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e x x x ( 2 0 0 8 ) x x x – x x x2

1. Introduction

Diabetes is a major cause of morbidity and mortality world-

wide [1,2]. The problem of diabetes is particularly relevant to

India as several studies have clearly documented an increased

ethnic susceptibility to diabetes in migrant Asian Indians [3–7].

Recent epidemiological studies have pointed to the growing

epidemic of diabetes in India [8–14]. Indeed, according to the

recent Diabetes Atlas produced by the International Diabetes

Federation (IDF), India is home to the largest number of people

with diabetes in the world, 40.9 million diabetic subjects in

2007, and these numbers are predicted to increase to 69.9

million by 2025 [15].

These projections are based on a few isolated studies

conducted in specific geographical locations and do not

take into consideration the increase in various environ-

mental risk factors, like increasing urbanization and

economic development. There is hence an urgent need for

a nation-wide surveillance system for non-communicable

diseases in general and diabetes in particular. The present

study is a collaborative effort of the World Health

Organization (WHO) and Indian Council of Medical Research

(ICMR) to develop a sustainable system for NCD risk factor

surveillance in India using the WHO STEPS approach [16].

This article reports on the risk factors for self-reported

diabetes in Indians from the first national NCD surveillance

project, which was conducted in India from April 2003 to

March 2005.

Fig. 1 – Indian national NCD risk fa

Please cite this article in press as: V. Mohan et al., Urban rural differe

ICMR Indian NCD risk factor surveillance, Diab. Res. Clin. Pract.

2. Materials and methods

2.1. Study centers

The national NCD risk factor surveillance was conducted in six

different geographical locations (East, South, North, West/

Central India) in India (Fig. 1). The centers were selected based

on the experience of the investigator in conducting studies on

NCDs, location of the center and institutional infrastructure

for long-term involvement in NCD surveillance.

2.2. Recruitment

Sample size was calculated using the means of the risk factors.

The WHO STEPS recommends surveillance of the population

aged 25–64. However, as exposure to risk factors start in

younger ages in India, the age group was chosen as 15–64 years

[17].

2.3. Sampling units

Each state in the country is divided into wards based on

geographical location by the Government of India. The

existing ward in the sampling areas was used as the primary

sampling unit in the urban and peri-urban/slum areas. For the

rural areas, the primary health centre (PHC) was selected

randomly from one district at each stage, and the village was

selected as the primary sampling unit for data collection.

ctor surveillance study centers.

nces in prevalence of self-reported diabetes in India—The WHO–

(2008), doi:10.1016/j.diabres.2007.11.018


d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e x x x ( 2 0 0 8 ) x x x – x x x 3


2.4. Sample size

The total sample size of the NCD risk factor surveillance was

44,537, rural 13,527 (6672 men and 6855 women), peri-urban/

slum 15,763 (7649 men and 8114 women) and urban 15,247

(7564 men and 7683 women). A minimum of 2500 subjects

aged between 15 and 64 years stratified by sex and 10-year age

group was available in each of the area (rural, peri-urban/slum

and urban) in each centre, except in the Delhi centre, where

rural sampling was not available.

2.5. Data collection

The study was undertaken based on the methodology adapted

from the WHO global STEP-wise approach for risk factor

surveillance for NCDs. Data collection was done through

active surveillance. Major risk factors were studied using

adapted and modified WHO’s STEPS approach. Data collected

included demography, occupation, literacy, tobacco use,

alcohol use, physical activity and dietary behaviour. History

of medical ailments like self-reported diabetes and hyperten-

Table 1 – Characteristics of study population

Parameters Rural (n = 13,524)

Age (years) 38.6 � 14.1

Body mass index (kg/m2)

Men 20.3 � 3.4

Women 20.8 � 4.0

Waist (cm)

Men 77 � 10

Women 74 � 12

Systolic blood pressure (mm Hg)

Men 126 � 18

Women 123 � 19

Diastolic blood pressure (mm Hg)

Men 77 � 12

Women 77 � 11

Educational status, n (%)

Illiterate 3609 (26.7)

Some schooling 8805 (65.1)

Graduate and above 1105 (8.2)

Physical activity, n (%)

Sedentary 4648 (35.0)

Moderate 5245 (39.5)

Vigorous 3377 (25.4)

Smoking, n (%)

Men 1783 (26.7)

Women 296 (4.3)

Generalized obesity, n (%)

Men 623 (9.4)

Women 961 (14.1)

Abdominal obesity, n (%)

Men 811 (12.2)

Women 1975 (29.6)

Missing data pertaining to various parameters were excluded from the re* p < 0.001 compared to subjects in rural area.** p < 0.001 compared to subjects in peri-urban/slum area.



sion were also collected. The questionnaires of STEPS was pre-

tested and suitably modified to fit Indian conditions after pilot

testing on a sub-population in each centre.

2.6. Anthropometry and clinical examination

Height and weight were measured and the body mass index

(BMI) was calculated in all study participants. Waist

circumference was measured using standard techniques.

Blood pressure was recorded in the sitting position in the

right arm to the nearest 1 mm Hg using the electronic

OMRON machine (Omran Corporation,Tokyo, Japan). Two

readings were taken 5 min apart and the mean of the two

was taken as the blood pressure. If the difference between

these two measurements was greater than 10 mm Hg for a

participant, a third measurement was done and the mean of

the two closest readings was recorded as the blood pressure

of the individual.

Ethical committee approval was obtained prior to the start

of the study and informed consent was obtained from all the

study subjects.

Peri-urban/slum (n = 15,760) Urban (n = 15,239)

39.0 � 14.0 39.3 � 14.2*

21.2 � 3.9* 23.1 � 4.2*

22.3 � 4.6* 24.0 � 4.9*,**

79 � 11* 84 � 15*

77 � 16* 82 � 13*,**

129 � 19* 131 � 19*

125 � 21* 127 � 21*,**

79 � 12* 80 � 12*

77 � 12* 78 � 11*,**

4,015 (25.5) 1,223 (8.0)*

10,536 (66.9) 10,771 (70.8)*

1,201 (7.6) 3,229 (21.2)*,**

6,431 (41.4)* 8,208 (56.1)*

6,905 (44.4)* 5,337 (36.5)*

2,212 (14.2)* 1,080 (7.4)*,**

2,625 (34.3)* 2,003 (26.5)

222 (2.7)* 53 (0.7)*,**

1,274 (16.7)* 2,316 (30.7)*

2,098 (26.1)* 2,956 (38.8)*,**

1,370 (17.9)* 2,333 (30.9)*

3,230 (41.1)* 4,354 (57.8)*,**

levant analysis, so the number of subjects may differ with variables.


(2008), doi:10.1016/j.diabres.2007.11.018




3. Definitions

3.1. Education level

Education level was categorized as illiterate if there was no

formal schooling, as some schooling if it was less than primary

schooling to high school completed and as graduate and above

if it was college/university completed or had a postgraduate

degree.

3.2. Smokers

Subjects who currently smoke tobacco daily were categorized

as smokers.

3.3. Physical activity

The Physical Activity Questionnaire (Global Physical Activity

Questionnaire, GPAQ—available in the website www.who.int/

chp/steps) used in this survey was developed by WHO for

physical activity surveillance in countries and collects

information on physical activity participation in three settings

(or domains) and sedentary behaviour. The domains include

activity at work, travel to and from places and recreational

activities. Study individuals were categorized based on a

physical activity questionnaire. The questionnaire had ques-

tions on job related and leisure time activities. Based on the

answers both these questions were graded separately as

sedentary, moderate and heavy.

Overall physical activity was then graded as sedentary,

moderate and vigorous, compiling both job related and leisure

time activities.

3.4. Diabetes

Self-reported diabetes was defined as diabetes diagnosed by a

physician, irrespective of diabetes control status.

3.5. Obesity

Obesity was defined if body mass index was �25 kg/m2 based

on WHO Asia Pacific guidelines [18].

3.6. Abdominal obesity

Abdominal obesity was defined as waist circumference

�90 cm for males and �80 cm for females as per modified

WHO Asia Pacific guidelines [18].

3.7. Statistical analysis

All data were computed on Epi-Info (Version 6), a public

domain program. Double entry of a subset of data and random

checking for errors were the measures taken for quality

assurance. The crude prevalence rate obtained in the present

study was age standardized to 2001 India census. One-way

ANOVA (with Tukey’s honest significant difference) or

Student’s t-test was used to compare groups for continuous

variables and Chi-square test to compare proportions. Trend

Chi-square test was used to compare the increase in



prevalence of self-reported diabetes across the different study

groups. Logistic regression analysis was carried out using self-

reported diabetes as the dependent variable and other risk

factors as independent variables. Thirty-four subjects did not

respond to the question on self-reported diabetes and hence

were excluded from all analysis on self-reported diabetes.

Similarly missing data pertaining to various parameters were

excluded from the relevant analysis, so the number of subjects

may differ with variables. All the analysis was done using

Windows-based SPSS statistical package (Version 10.0, Chi-

cago) and a p value of <0.001 was considered for statistical

significance.

4. Results

4.1. Characteristics of the study population

Table 1 presents the characteristics of study subjects based on

their residence. Body mass index, waist circumference,

systolic and diastolic blood pressure were highest among

urban residents followed by the peri-urban/slum residents

and the lowest in rural residents (p < 0.001). Over 25% of the

rural residents were illiterate compared to 8.0% in urban areas

while percentage of graduates was higher in urban areas. With

regard to physical activity, more than 50% of the urban

residents had a sedentary lifestyle while nearly 25% of rural

inhabitants were involved in vigorous physical activity.

Smoking was most common among peri-urban/slum men

compared to their rural and urban counterparts. Obesity and

abdominal obesity were more common in urban residents,

followed by peri-urban/slum and lowest among rural resi-

dents (p < 0.001).

4.2. Prevalence of self-reported diabetes

Table 2 shows that the lowest prevalence of self-reported

diabetes was recorded in rural (3.1%) followed by peri-urban/

slum with 3.2% and the highest prevalence was observed in

urban areas (7.3%) (urban: p < 0.001 compared to peri-urban/

slum and rural areas). There was a geographical difference in

the prevalence of self-reported diabetes, with the centres in

southern states having a higher prevalence of self-reported

diabetes compared with north and central India. Thus, the

overall prevalence of self-reported diabetes was highest in

Trivandrum in Kerala (9.2%), followed by Chennai in

Tamilnadu (6.4%) and Delhi (6.0%). This was followed by

Ballabgarh in North India (2.7%), Dibrugargh in East India

(2.4%) and the lowest was observed in Nagpur in West/Central

India (1.5%). Similar trends were observed even when

categorized based on residential areas as urban, peri-

urban/slum and rural areas, except for urban areas where

Delhi had higher rates than Chennai and Dibrugarh had

higher rates than Ballabgarh.

Fig. 2 shows the age wise distribution of self-reported

diabetes in the study population. Prevalence of self-reported

diabetes increased with increase in age in the rural (trend Chi-

square 309.1, p < 0.001), peri-urban/slum (trend Chi-square

385.9, p < 0.001) and urban (trend Chi-square 966.4, p < 0.001)

areas. At every age point, the prevalence of self-reported


(2008), doi:10.1016/j.diabres.2007.11.018

http://www.who.int/chp/steps

http://www.who.int/chp/steps


Table 2 – Centre-wise prevalence of self-reported diabetes

Regions Places Prevalence of self-reported diabetes (%)

Rural(n = 13,522)

Peri-urban/slum(n = 15,751)

Urban(n = 15,230)

Overall(n = 44,503)

North India Delhi (n = 5103) – 1.8 10.3# 6.0

Ballabgarh (n = 7990) 1.1 2.3* 4.8*,# 2.7

South India Chennai (n = 7847) 3.9 6.6* 8.7*,## 6.4

Trivandrum (n = 7537) 9.6 6.6* 11.2**,# 9.2

East India Dibrugarh (n = 8365) 0.6 1.4** 5.5*,# 2.4

West/Central India Nagpur (n = 7661) 0.6 0.6 3.2*,# 1.5

Overall (n = 44,503) 3.1 3.2 7.3*,# 4.5

*p < 0.001 and **p < 0.05 compared to subjects in rural area. #p < 0.001 and ##p < 0.05 compared to subjects in peri-urban/slum area.



diabetes was higher among the urban residents compared to

peri-urban/slum (statistically significant at all age groups) and

rural residents (reached statistical significance after the age of

25 years).

4.3. Risk factors of diabetes

Table 3 presents the characteristics of subjects with and

without diabetes. Diabetic subjects were older (p < 0.001), had

higher body mass index (p < 0.001), waist circumference

(p < 0.001), systolic (p < 0.001) and diastolic (p < 0.001) blood

pressure compared to non-diabetic subjects. Diabetic subjects

were also more sedentary (p < 0.001) and more literate than

non-diabetic subjects (p < 0.001). Prevalence of generalized

obesity (p < 0.001) and abdominal obesity (p < 0.001) were also

higher among diabetic subjects but smoking rates were lower

(p < 0.001).

4.4. Residential area and diabetes

Table 4 shows the logistic regression analysis using self-

reported diabetes as the dependent variable and residential

area, physical activity, abdominal obesity and literacy rates

as independent variables. Subjects residing in urban areas

had significantly higher rates of self-reported diabetes

compared to rural residents (odds ratio (OR): 2.48, 95%

confidence interval (CI): 2.21–2.78, p < 0.001), which per-

Fig. 2 – Age-wise prevalence rates of self-rep



sisted even after adding age ( p < 0.001) into the model. There

was no significant increase in risk among peri-urban slum

residents compared to their rural counterparts (data not

shown).

4.5. Physical activity and diabetes

Subjects with moderate grade activity had 1.69 times higher

(p < 0.001), and those with sedentary activity, 2.3 times higher

(p < 0.001) rates of self-reported diabetes compared to those

with vigorous activity. Introducing age into the model did not

change the effect of physical activity on diabetes.

4.6. Abdominal obesity indices and diabetes

The risk for self-reported diabetes was four times higher

among subjects with abdominal obesity compared to those

without obesity (OR: 4.5). Adjusting for age reduced the odds

ratio to 3.55, but it was still statistically significant

( p < 0.001).

4.7. Literacy rates and diabetes

Literacy showed an association with self-reported diabetes

and education levels of graduate or above had 3.0 times

(p < 0.001) increased risk of having self-reported diabetes after

adjusting for age.

orted diabetes in the study population.


(2008), doi:10.1016/j.diabres.2007.11.018


Table 4 – Logistic regression analysis using self-reported diabetes as the dependent variable

Unadjusted Adjusted for age

Oddsratio

95% confidenceintervals

Adjustedfor age

Oddsratio

95% confidenceintervals

P value

Residential area

Rural (reference) 1.0 – – – – –

Urban 2.48 2.21–2.78 <0.001 2.48 2.21–2.79 <0.001

Physical activity

Vigorous activity (reference) 1.0 – – – – –

Moderate 1.69 1.42–2.00 <0.001 1.52 1.28–1.81 <0.001

Sedentary 2.30 1.95–2.71 <0.001 1.79 1.51–2.12 <0.001

Abdominal obesity

Subjects without abdominal

obesity (reference)

1.0 – – – – –

Subjects with abdominal obesity 4.50 4.27–5.17 <0.001 3.55 3.22–3.91 <0.001

Literacy levels

Illiterate (reference) 1.0 – – – – –

Some schooling 1.38 1.20–1.50 <0.001 2.51 2.48–2.89 <0.001

Graduate and above 1.20 0.99–1.50 NS 3.02 2.45–3.71 <0.001

Table 3 – Characteristics of non-diabetic and diabetic subjects

Parameters Non-diabetic subjects (n = 42,466) Diabetic subjects (n = 2023) p-Value

Age (years) 38 � 14 52 � 10 <0.001

Males n (%) 20,853 (49.1) 1017 (50.3) –

BMI (kg/m2)

Men 21.5 � 4.0 24.3 � 4.0 <0.001

Women 22.2 � 4.7 26.0 � 4.9 <0.001

Waist (cm)

Men 80 � 13 90 � 12 <0.001

Women 78 � 14 90 � 13 <0.001

Systolic blood pressure (mm Hg)

Men 128 � 18 142 � 22 <0.001

Women 124 � 20 142 � 24 <0.001

Diastolic blood pressure (mm Hg)

Men 79 � 12 85 � 12 <0.001

Women 77 � 11 84 � 11 <0.001

Educational status, n (%)

Illiterate 8,552 (20.1) 292 (14.4)

Some schooling 28,675 (67.5) 1435 (70.9) <0.001

Graduate and above 5,239 (12.3) 296 (14.6)

Physical activity, n (%)

Sedentary 18,203 (43.9) 1082 (54.6)

Moderate 16,754 (40.4) 730 (36.9) <0.001

Vigorous 6,501 (15.7) 168 (8.5)

Smoking, n (%)

Men 6,150 (29.5) 259 (25.5) <0.001

Women 558 (2.6) 13 (1.3) <0.001

Generalized obesity, n (%)

Men 3,789 (18.2) 424 (41.9) <0.001

Women 5,444 (25.4) 569 (56.8) <0.001

Abdominal obesity, n (%)

Men 3,978 (19.1) 535 (52.6) <0.001

Women 8,737 (41.5) 821 (82.0) <0.001



4.8. Cumulative effect of risk factors

The cumulative effect of risk factors was determined by

combining the risk factors and looking at the prevalence of



self-reported diabetes (Fig. 3). The prevalence of self-reported

diabetes among rural subjects with no abdominal obesity and

vigorous activity was 0.7%, which dramatically increased to

9.9% in rural subjects with abdominal obesity with sedentary


(2008), doi:10.1016/j.diabres.2007.11.018


Fig. 3 – Prevalence of self-reported diabetes in relation to

residential area, abdominal obesity and physical

inactivity.



activity (trend Chi-square 246.4, p < 0.001). Similarly among

urban subjects, the prevalence of self-reported diabetes rises

from 1.8% in those without abdominal obesity and with

vigorous activity to 11.3% in those with abdominal obesity and

sedentary lifestyle (trend Chi-square 141.8, p < 0.001). This

figure clearly shows the independent contributions of abdom-

inal obesity, physical inactivity and urban residence on

diabetes prevalence in India.

4.9. Regional differences in prevalence of diabetes

Southern India (Chennai (6.4%) and Trivandrum (9.2%), mean

(7.7%)) had higher prevalence of self-reported diabetes

compared to northern India (Delhi (6.0%) and Ballabgarh

(2.7%), mean (4.0%)), eastern India (Dibrugarh (2.4%)) and

western/central India (Nagpur (1.5%)). The higher prevalence

rates of diabetes correlated well with higher rates of obesity in

the respective regions generalized obesity (South India: 27.2%,

North India: 23.8%, East India: 15.9%, West India: 15%, trend

Chi-square: 12.03, p = 0.001) and abdominal obesity (South

India: 39.6%, North India: 34.2%, East India: 20.7%, West India:

19.7%, trend Chi-square: 33.28, p < 0.001). There were differ-

ences in physical activity and literacy levels in different

regions of India but they did not correlate with the prevalence

of diabetes in the respective regions.

5. Discussion

The main findings of the study are the following: (1) crude

prevalence rate of self-reported diabetes was highest in urban,

intermediate in peri-urban/slum and lowest in rural areas in

India, (2) urban residence, abdominal obesity and physical

inactivity were the main risk factors for diabetes.

The first nation-wide diabetes prevalence study was

conducted by ICMR in the year 1972 and covered six different

states of India. Prevalence of diabetes in this study was

recorded as 2.1% in urban areas and 1.5% in rural areas [19].

Following this there were several epidemiological studies in



different geographical areas of India which reported pre-

valence ranging from 3.8 to 15.5% [20–22]. This study was

conducted at the national level in urban, peri-urban and rural

areas using standardized WHO STEPS methodology. Since it is

a national surveillance project the results are of great

significance as they can be used as baseline for future

surveillance studies. The overall crude prevalence of self-

reported diabetes was 7.3% in urban, 3.2% in peri-urban/slum

and 3.1% in rural areas. Assuming from earlier published

studies in India that for every known case of diabetes, there

would be at least one unknown [8,10], one could assume that

the figures for total diabetes (self reported + undiagnosed)

would be 14.6% (urban), 6.4% (peri-urban) and 6.2% in rural

areas. These figures are remarkably higher than those

reported in 1970 [19] and are similar to those recently reported

from India [8,10]. Only one recent study done in southern India

called CURES (Chennai Urban Rural Epidemiology Study) [10]

had used plasma glucose measurement. This study reported

an overall diabetes prevalence of 15.5 and 6.1% of known

diabetes (i.e., 9.4% unknown diabetes). Therefore the ratio of

all diabetes/known diabetes in the study is 2.5. In addition, the

recently published Diabetes Atlas [23] states that to account

for unknown diabetes, the prevalence of diabetes for Canada

and US was multiplied by a factor of 1.5, and for the other

countries it was multiplied by 2.0. An earlier nation-wide study

on prevalence of diabetes in India (which, however, used

capillary blood glucose) reported the ratio of newly diagnosed

to known diabetes as 2.5 for overall India, 2.1% for urban India

and 4.2% for rural India [24]. We have chosen to be

conservative and therefore have multiplied the known

diabetes prevalence by 2, which is exactly what the IDF

Diabetes Atlas recommends. Moreover, as a 15-year age cut

point was used in this study compared to 20 years in most

earlier studies, the prevalence rates in this study would be

even higher had the 20-year cut point been used.

A recent nation-wide study [24], prevalence of diabetes in

India study (PODIS) reported the overall prevalence of diabetes

in urban and rural to be 5.9 and 2.7%, respectively, which is

much lower than that reported in this study, although the

PODIS had used glucose tolerance tests to detect undiagnosed

diabetes. The lower prevalence rates observed in PODIS could

be due to the following reasons: (i) sampling areas were

categorized as urban and rural based on the population. Areas

having a population over 100,000 were designated as urban,

while those less than 100,000 were designated as rural. (ii)

Diagnosis of diabetes was based on capillary blood sample

using venous plasma criteria, which could obviously under-

estimate the prevalence of diabetes. (iii) Correlation of 2 h

post-load capillary blood glucose with venous sample was

quite low (0.62).

An interesting observation in this study is that higher

prevalence of self-reported diabetes was observed in southern

India compared to northern, eastern and western part of the

country (except Delhi urban residents). Other studies have

also shown similar results [25,26]. Our study results are in

agreement with the earlier national urban diabetes survey

(NUDS), which showed that Hyderabad, Chennai and Banga-

lore in the south had higher prevalence rates compared to

Delhi, Mumbai or Kolkatta in north, west and east of India,

respectively [9]. In this study, we observed that the higher


(2008), doi:10.1016/j.diabres.2007.11.018




rates of generalized and abdominal obesity were associated

with higher rates of diabetes in the respective regions. The

fact that south Indians consume rice-based diets, which

have a higher glycemic index compared to northern India

where the staple food is wheat, could be another contribut-

ing factor. Variations in genetic factors also need to be

studied to explain these differences. Finally, one cannot rule

out the fact that more frequent screening of the population

in some places, e.g., South India/Delhi may have contributed

to the higher prevalence rates of known diabetes in these

regions. The high prevalence of diabetes in Trivandrum

could be explained by the fact that Trivandrum is in Kerala

state which is one of the most urbanized states in India.

Indeed, a recent study [27] from Ernakulam district in Kerala

has reported a prevalence of 19.5%, which is the highest

reported in India so far.

In developing countries, the prevalence of diabetes is

higher in urban than rural while in developed countries, the

prevalence is higher in rural than urban. In India, in the year

2000, the prevalence of diabetes was 12.4% in urban [28] and

2.5% in rural areas [29] and in 2004, the prevalence was 15.5%

in urban [10] and 2.7% in rural areas [24]. In developed

countries like Australia, the reverse situation is seen and the

prevalence is higher in rural (11.6%) [30] than in urban areas

(7.4%) [31]. Thus the urban–rural differences in the prevalence

of diabetes are not universal. Both urban and rural difference

and geographical difference could also be explained by

awareness and knowledge about diabetes. Literacy rates

among urban residents were higher compared to their rural

and slum counterparts. This could play a major role in

increased prevalence of self-reported diabetes and indeed

literacy did come as a factor associated with diabetes in this

study. Literate people are more likely to know about self-

reported diabetes compared to illiterate people.

The main risk factors for self-reported diabetes were

abdominal obesity, physical inactivity and urban residence.

Earlier studies both in West [32,33] and in India [8–10] have

consistently reported an association of diabetes with abdom-

inal obesity. The mean BMI of this study population ranged

between 20.3 and 23.5 kg/m2, which is much lower than the

cut off of >25 kg/m2 suggested by WHO Asia Pacific guidelines

for obesity [18]. Similarly, the waist circumference was also

lower than the cut off of �80 cm for women and �90 cm for

men recommended by WHO Asia Pacific guidelines to define

abdominal obesity. This indicates that the thresholds for BMI

and waist to develop diabetes may be lower in Asian Indians

compared to other ethnic groups. This is consistent with

earlier reports describing this peculiar phenotype, which has

been referred to as the ‘Asian Indian or South Asian

Phenotype’ [34–38].

Physical inactivity has been consistently shown to be a risk

factor for diabetes. An earlier population-based study in

Chennai showed that prevalence of diabetes was higher

among subjects with light grade activity compared to heavy

grade activity [39]. In the present study, subjects with

sedentary activity had 2.2 times higher risk for diabetes

compared to those with vigorous activity. The fact that only

7.4% of the urban residents performed vigorous activity

compared to 25.4% in rural inhabitants could also partly

explain the higher prevalence of diabetes in urban people.



Increased prevalence of abdominal obesity and decreased

physical activity is a consequence of economic transition and

nutritional transition. Urbanization has played a major role in

the epidemiological transition cum health transition. In this

regard, this study has yielded interesting results as urban

residents had increased prevalence of diabetes compared to

peri-urban/slum and rural residents. However, even physi-

cally active, non-obese urban residents had higher risk of

having diabetes compared to their rural counterparts. Further,

the influence of affluence is obvious from the fact that urban

residents had higher prevalence of diabetes compared to their

peri-urban/slum counterparts, which in turn was higher than

the rural residents. This is in agreement with earlier studies

[22,40] indicating urban rural differences in the prevalence of

diabetes. It has recently been shown that environmental

pollution in urban areas is an independent risk factor for

diabetes [41]. Future studies should look at the role of pollution

in increasing risk of diabetes in urban Indians.

Another interesting observation in this study is that

abdominal obesity and physical inactivity had a synergistic

effect on the diabetes risk. Thus, among urban rural residents

without sedentary life style or abdominal obesity, the

prevalence of diabetes was 0.7%; this increased to 1.9% if

the subjects had sedentary life style and further increased to

11.3% if they also had abdominal obesity. This underscores

the importance of primary prevention of diabetes by

increasing physical activity and prevention of obesity as part

of a national programme to prevent diabetes and cardiovas-

cular disease.

One of the limitations of the study is that the study was not

performed on a representative sample of India with regard to

age distribution as study subjects were recruited based on age-

specific criteria. Another limitation is that diabetes was

diagnosed based on self-reported diabetes. However, the

STEPS 3 of the NCD risk factor surveillance, currently ongoing

on a subset of study subjects, includes collection of blood

samples for detecting undiagnosed diabetes. Finally, this

study being a cross-sectional study, it cannot provide evidence

for a cause and effect relationship between the association of

risk factors with diabetes.

In conclusion, this nation-wide NCD risk factor surveil-

lance study shows that the prevalence of self-reported

diabetes in India is highest in urban (7.3%), intermediate in

peri-urban 3.2% and lowest in rural area (3.1%) among adults

aged �15 years. Urban residence, abdominal obesity and

physical inactivity are the risk factors for diabetes in this

study.

Acknowledgements

The NCD risk factor surveillance is supported by the World

Health Organization (WHO) India Office and the Indian Council

of Medical Research (ICMR), New Delhi and the Government of

India under WHO—Government of India Collaborative Pro-

gramme. The technical support from Dr. Cherian Varghese is

gratefully acknowledged. We thank the study coordinators

and field staff at the various centres for their help with this

study. Most importantly we thank all the participants of this

study for their cooperation in conducting this survey.


(2008), doi:10.1016/j.diabres.2007.11.018




Conflict of interest

The authors state that they have no conflict of interest.

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