mauritius has a population of 1.3 million people , which comprises 68% of south asian ( indian ) origin , 3% of chinese , 27% of african ( creole ) , and 2% of franco - mauritian . in 1987 and 2009 , population - based surveys using similar standardized protocols were conducted in mauritius ( 3,4 ) . in 1987 , 11 randomly selected ( with probability proportional to size ) population clusters were surveyed . in this survey , nine index clusters were chosen : one randomly selected from each of the nine districts in mauritius . then , two neighboring clusters were chosen surrounding the index cluster to form a  super cluster .  from this super cluster , one in three households was randomly selected and one adult per household was invited to participate . a total of 11,454 people were recruited over the two surveys ( 1987 , n = 5,083 , age 2274 years ; 2009 , n = 6371 , age 2074 years ) . the response rates for the 1987 ( 3 ) and the 2009 survey were both over 85% . the ethics committee of the ministry of health and quality of life , mauritius , approved both surveys . waist circumference was measured using different methods in each survey but was adjusted accordingly based on previously published comparisons ( 5 ) . bmi ( measured as kilograms divided by the square of height in meters ) was calculated from measured body weight and height . in both studies , blood was collected after an overnight fast of 8 h. specimens for glucose were collected into fluoride / oxalate tubes , and glucose was assayed onsite using a ysi glucose analyzer ( ysi , yellow springs , oh ) instrument at both surveys . glucose tolerance status was determined according to 1999 world health organization criteria ( 6 ) . in 1987 , blood pressure was measured with a standard mercury sphygmomanometer , while in 2009 , blood pressure was measured using an automated blood pressure monitor ( omron digital auto blood pressure monitor sem-1 ) . participants reporting a history of diabetes and using insulin or hypoglycemia medication or with fpg or 2hrpg in the diabetes range were defined as having diabetes . < 7.0 mmol / l and 2hrpg 7.8 but < 11.1 mmol / l indicated impaired glucose tolerance ( igt ) , fpg 6.16.9 mmol / l and 2hrpg < 7.8 mmol / l indicated impaired fasting glucose ( ifg ) , and both fpg < 6.1 mmol / l and 2hrpg < 7.8 hypertension was defined as mean systolic blood pressure 140 mmhg , mean diastolic blood pressure 90 mmhg , or treatment with antihypertensive medication . in 1987 and 2009 , similar interview - administered questionnaires were conducted to collect demographic , lifestyle , and medical history information including smoking , ethnicity , and family history of diabetes ( first - degree family members with diabetes ) . habitual physical activity was collected by different questionnaires in 1987 and 2009 . in 1987 , leisure and occupational physical activity was categorized on a four - level scale using questions developed specifically for the survey : sedentary ( housebound ) , light ( gardening and walking ) , moderate ( e.g. , aerobic activity 12 days per week ) , and heavy ( e.g. , aerobic activity 3 days per week ) , based on usual patterns over past years . in 2009 , the general physical activity questionnaire ( 8) , which has been validated in an indian population , was used to collect information about habitual physical activity . because the measurement of physical activity was different at the two points , we applied a conservative approach to categorize 2009 participants into equivalent 1987 physical activity level categories . in brief , if participants in 2009 reported doing vigorous heavy physical activity for 3 days per week , they were categorized under the category  heavy  levels of physical activity and those reporting vigorous activity 12 days per week were categorized into the moderate level category . the remaining participants were classified into a combined category of sedentary and light physical activity . changes in the distribution of fpg and 2hrpg between surveys were illustrated by tukey mean difference plots ( 9 ) . in these plots , the difference between mean plasma glucose in the corresponding 12 quantiles of the two different surveys is plotted against the mean of the combined quantiles . quantiles of 2hrpg that were outliers were excluded . to create the 12 quantiles , we used 2.5 and 97.5 percentiles as cut points to define the lowest and highest groups . polytomous multinominal logistic regression was used to test whether the glucose distributions were statistically different between the two surveys . for this , the 12 groups were created in the same way but all survey data were combined . these groups were used as the dependent outcome variable , and the effect of the year of survey was examined in crude models ( year of survey only ) , followed by models adjusted by age , sex , ethnicity , waist circumference , hypertension , physical activity ( occupational and leisure ) , and smoking . diabetes prevalence of both surveys was age and sex standardized to the 2008 population of mauritius aged 2274 years . change in diabetes prevalence between the two cohorts was analyzed by logistic regression with diabetes status as the dependent outcome and year of survey as the independent outcome . the odds ratio ( or ) of year of survey was computed in a crude model and after adjustment for the covariates as listed in the tables . to account for the clustered sampling design of the surveys stata ( version 11.2 ; statacorp , college station , tx ) was used for all analyses . mauritius has a population of 1.3 million people , which comprises 68% of south asian ( indian ) origin , 3% of chinese , 27% of african ( creole ) , and 2% of franco - mauritian . in 1987 and 2009 , population - based surveys using similar standardized protocols were conducted in mauritius ( 3,4 ) . in 1987 , 11 randomly selected ( with probability proportional to size ) population clusters were surveyed . in this survey , nine index clusters were chosen : one randomly selected from each of the nine districts in mauritius . then , two neighboring clusters were chosen surrounding the index cluster to form a  super cluster .  from this super cluster , one in three households was randomly selected and one adult per household was invited to participate . a total of 11,454 people were recruited over the two surveys ( 1987 , n = 5,083 , age 2274 years ; 2009 , n = 6371 , age 2074 years ) . the response rates for the 1987 ( 3 ) and the 2009 survey were both over 85% . the ethics committee of the ministry of health and quality of life , mauritius , approved both surveys . waist circumference was measured using different methods in each survey but was adjusted accordingly based on previously published comparisons ( 5 ) . bmi ( measured as kilograms divided by the square of height in meters ) was calculated from measured body weight and height . in both studies , blood was collected after an overnight fast of 8 h. specimens for glucose were collected into fluoride / oxalate tubes , and glucose was assayed onsite using a ysi glucose analyzer ( ysi , yellow springs , oh ) instrument at both surveys . glucose tolerance status was determined according to 1999 world health organization criteria ( 6 ) . in 1987 , blood pressure was measured with a standard mercury sphygmomanometer , while in 2009 , blood pressure was measured using an automated blood pressure monitor ( omron digital auto blood pressure monitor sem-1 ) . participants reporting a history of diabetes and using insulin or hypoglycemia medication or with fpg or 2hrpg in the diabetes range were defined as having diabetes . < 7.0 mmol / l and 2hrpg 7.8 but < 11.1 mmol / l indicated impaired glucose tolerance ( igt ) , fpg 6.16.9 mmol / l and 2hrpg < 7.8 mmol / l indicated impaired fasting glucose ( ifg ) , and both fpg < 6.1 hypertension was defined as mean systolic blood pressure 140 mmhg , mean diastolic blood pressure 90 mmhg , or treatment with antihypertensive medication . in 1987 and 2009 , similar interview - administered questionnaires were conducted to collect demographic , lifestyle , and medical history information including smoking , ethnicity , and family history of diabetes ( first - degree family members with diabetes ) . habitual physical activity was collected by different questionnaires in 1987 and 2009 . in 1987 , leisure and occupational physical activity was categorized on a four - level scale using questions developed specifically for the survey : sedentary ( housebound ) , light ( gardening and walking ) , moderate ( e.g. , aerobic activity 12 days per week ) , and heavy ( e.g. , aerobic activity 3 days per week ) , based on usual patterns over past years . in 2009 , the general physical activity questionnaire ( 8) , which has been validated in an indian population , was used to collect information about habitual physical activity . because the measurement of physical activity was different at the two points , we applied a conservative approach to categorize 2009 participants into equivalent 1987 physical activity level categories . in brief , if participants in 2009 reported doing vigorous heavy physical activity for 3 days per week , they were categorized under the category  heavy  levels of physical activity and those reporting vigorous activity 12 days per week were categorized into the moderate level category . the remaining participants were classified into a combined category of sedentary and light physical activity . changes in the distribution of fpg and 2hrpg between surveys were illustrated by tukey mean difference plots ( 9 ) . in these plots , the difference between mean plasma glucose in the corresponding 12 quantiles of the two different surveys is plotted against the mean of the combined quantiles . quantiles of 2hrpg that were outliers were excluded . to create the 12 quantiles , we used 2.5 and 97.5 percentiles as cut points to define the lowest and highest groups . polytomous multinominal logistic regression was used to test whether the glucose distributions were statistically different between the two surveys . for this , the 12 groups were created in the same way but all survey data were combined . these groups were used as the dependent outcome variable , and the effect of the year of survey was examined in crude models ( year of survey only ) , followed by models adjusted by age , sex , ethnicity , waist circumference , hypertension , physical activity ( occupational and leisure ) , and smoking . diabetes prevalence of both surveys was age and sex standardized to the 2008 population of mauritius aged 2274 years . change in diabetes prevalence between the two cohorts was analyzed by logistic regression with diabetes status as the dependent outcome and year of survey as the independent outcome . the odds ratio ( or ) of year of survey was computed in a crude model and after adjustment for the covariates as listed in the tables . to account for the clustered sampling design of the surveys , we used survey commands in the analyses . stata ( version 11.2 ; statacorp , college station , tx ) was used for all analyses . table 1 shows that in 2009 , participants had significantly larger bmi and waist and hip circumferences than in 1987 and were significantly older than in 1987 . they were also significantly less likely to smoke but were more likely to have hypertension and to undertake leisure - time physical activity , though less likely to undertake physical activity at work . characteristics of survey populations in mauritius the age - standardized prevalence of diabetes , igt , and ifg and by age group is shown in table 2 . between 1987 and 2009 , the prevalence of diabetes increased by 64% , of igt by 3% , and of ifg by 126% . diabetes prevalence increased by ~64% in south asians , ~63% in africans , and ~17% in chinese . igt prevalence increased by 10% in south asians and decreased by 12% in africans and chinese . the prevalence of ifg increase by 224% in south asians and 39% in africans and decreased by 2% in chinese . the prevalence of diabetes significantly increased from 1987 to 2009 in all age groups except for those aged < 34 years ( table 2 ) . prevalence of categories of abnormal glucose tolerance according to age - group and ethnicity when 2hrpg was categorized into < 7.8 , 7.811.0 , and 11.1 mmol / l independent of fpg , the proportion of those in the middle and upper groups increased between the two surveys by 19.5 and 14.4% , respectively . when fpg was categorized into < 6.1 , 6.16.9 , and 7.0 mmol / l , the proportion in the middle and upper groups increased by 82 and 105% , respectively . among those with diabetes in both surveys , 14 and 35% were diagnosed , respectively , by their fpg and 2hrpg values only in 1987 . in 2009 , 22 and 28% were diagnosed by their fpg and 2hrpg only . the geometric means of fpg and 2hrpg were significantly higher in 2009 than in 1987 after adjustment for age , sex , ethnicity , and waist circumference . with further adjustment for physical activity ( leisure and occupational ) , smoking , and hypertension , mean fpg and 2hrpg remained significantly higher in 2009 than in 1987 but mean 2hrpg was slightly higher in 1987 than in 2009 ( p < 0.001 ) ( table 3 ) . geometric means and absolute changes in fpg and 2hrpg among mauritian adults table 4 shows a series of logistic regression models that are adjusted with demographic , lifestyle , and biological risk factors to examine which of these groups of variables could explain the increase in prevalence of diabetes from 1987 to 2009 . the ors for diabetes were attenuated after the addition of demographic factors ( model 2 ) and lifestyle - based factors ( model 3 ) . adjusting for waist circumference and bmi attenuated the difference further ( model 4 ) , as did the addition of hypertension ( model 5 ) . the addition of family history of diabetes completely explained the difference in diabetes prevalence in the total population ( or 1.11 [ 95% ci 0.991.25 ] ) and in men ( 1.03 [ 0.861.22 ] ) but not in women ( 1.32 [ 1.131.55 ] ) . ors of having diabetes in 2009 compared with 1987 supplementary figure 1 ( available in the supplementary data ) shows that fpg and 2hpg rose at all levels of blood glucose between 1987 and 2009 . for fpg , the increase was greater at higher levels of blood glucose . with the use of crude polytomous multinominal logistic regression with fpg in 12 groups , this differential increase was significant for each of the 12 groups ( p < 0.001 ) . when these models were adjusted for age , sex , ethnicity , waist circumference , hypertension , smoking , and family history of diabetes , the difference in distributions remained significant . similar patterns were observed in men and women ( data not shown ) . for 2hrpg , in multinominal regression , the shift in glucose between years was significant for each of the 12 groups in crude models and remained significant after adjustment for sex , ethnicity , waist circumference , hypertension , smoking , and family history of diabetes ( p < 0.001 ) . our analyses show that diabetes prevalence has increased by 64% over 22 years in mauritius . the prevalence of igt was relatively stable over the 22 years , while the prevalence of ifg increased by over 100% . the increase can be fully explained in men , but not in women , by a combination of differences in age distribution and modifiable ( lifestyle ) factors . the increase in diabetes prevalence is accompanied by significant increases in means of fpg and 2hrpg affecting the whole population , with a greater increase in fpg seen at the upper end of the fpg distribution . the distribution of ethnicities in mauritius reflects approximately two - thirds of the world population . thus , epidemiological data from this nation s population provides a global perspective and will be relevant in many settings . the findings suggest that the majority of the change in prevalence is due to modifiable factors and is not due to selection bias , diagnostic bias , or change in mortality rates . both surveys were sampled across randomly selected clusters with excellent response rates and similar survey methods . diabetes prevalence most likely has not risen as a result of declining mortality rates because the increase in diabetes prevalence in younger ages ( 3544 years ) , in which mortality has not changed significantly over time , was 68% . we have shown that age and modifiable ( lifestyle based ) risk factors are responsible for all of the increase in diabetes prevalence in men and most of the increase in women . the greatest contributory factors were obesity and family history of diabetes . we can not be certain , however , of precisely what information is captured by family history of diabetes . while it captures genetic risk of diabetes , family history probably represents more than this . one may argue that since diabetes was more common in 2009 than in 1987 , family history of diabetes collected in 2009 could simply reflect this and therefore may be inappropriate to include as an explanatory variable . however , we believe that family history of diabetes may also be a good surrogate for measuring lifestyle and cultural factors such as diet . we were unable to directly measure the effect of a changing diet because methods were not directly comparable across the two surveys . in 2010 , mauritius had the fourth highest prevalence of diabetes in the world ( 1 ) . we show that diabetes prevalence increased by 64 and 62% among men and women , respectively , over 22 years . this increase was observed in those of south asian and african descent but was much smaller in chinese . a study of 60-year - old danes showed that diabetes prevalence had increased by 38% over 22 years ( 10 ) . the increase in diabetes prevalence in our study is higher than that reported in the total population of the danish study , but the estimate of increase in diabetes prevalence was similar in men . there are some key differences between populations in both studies in terms of age range and ethnicity that prevent close comparisons . unlike the danish study , our study shows that the increase in diabetes over time was not due to concurrent increases in obesity alone . our reports are similar to the change in prevalence observed in the u.s . using national health and nutrition examination survey ( nhanes ) data , which showed an increase in prevalence of diabetes of 51% over the period of 19881994 to 20052006 ( 11 ) . more recently , a study in scotland showed an increase of 80% in diabetes prevalence over the period of 20032008 ( 12 ) . the relative stability of the prevalence of igt over time observed in this survey is consistent with our previous work in mauritius documenting changes between 1987 and 1998 . however , our findings of a doubling ( and greater in some ethnicities ) in the prevalence of ifg are not consistent with previous findings in mauritius or in other countries . using nhanes data , cowie et al . ( 11 ) showed that the prevalence of igt and the prevalence of ifg were relatively stable between 19881994 and 20052006 . we also found that although both 2hrpg and fpg increased over the time period , fpg increased more than 2hrpg and more participants developed diabetes via their fpg value versus their 2hrpg value . this is consistent with the hypothesis that obesity is more related to fpg than to 2hrpg ( j. tuomilehto et al . when 2hrpg and fpg glucose were examined in categories independent of each other , we found that the increase in the proportion of those in the ifg classes of 6.16.9 and 7.0 mmol / l was much larger than the increase in the proportion in the categories 7.811.1 and 11.1 for both fpg and 2hrpg , all parts of the distribution showed increases in plasma glucose . the magnitude of the increase in glucose was larger at the upper than at the lower part of the glucose distribution . this was more obvious in the fpg distribution and less so with the 2hrpg distribution . given the different instruments used to collect physical activity information , we were only able to account for physical activity using a crude method . further , we were not able to assess the impact of changing dietary patterns on the increase in diabetes prevalence . furthermore , we can not rule out that the use of two different methods to measure blood pressure in the two surveys may have influenced our results . the projections of diabetes for the coming years are modeled on expected changes in demographics and do not consider changes in modifiable risk factors such as obesity ( 1 ) . since much of the increase in diabetes prevalence can be explained by lifestyle factors , it is likely that these projections are an underestimate . the sheer magnitude of the increases in diabetes in 2009 in mauritius portends a bleak future for mauritians in terms of diabetes complications , associated disorders , and the costs of diabetes - related health care .
objectivesecular trends in the epidemiology of diabetes are best described by studying the same population over time , but few such studies exist . using surveys from mauritius in 1987 and 2009 
 , we examined 1 ) the change in the prevalence of diabetes , 2 ) the extent to which changes in traditional diabetes risk factors explained the increase , and 3 ) the change in the distribution of plasma glucose levels over time.research design and methodsindependent population - based surveys were undertaken in mauritius in 1987 and 2009 using similar methodology in adults aged 2074 years . 
 physical measurements and fasting blood samples were taken , and an oral glucose tolerance test was performed at both surveys.resultsthe age - standardized prevalence of diabetes in 2009 was 22.3% ( 95% ci 20.024.6 ) among men and 20.2% ( 18.322.3 ) among women , representing an increase since 1987 of 64 and 62% among men and women , respectively . 
 concurrent changes in the distribution of age , ethnicity , waist circumference , bmi , physical activity , smoking , family history of diabetes , and hypertension explained more of the increase in the prevalence of diabetes in men than in women . 
 increases in plasma glucose ( especially fasting glucose ) were seen across the population but were greater at the upper levels.conclusionsin mauritius , there has been a marked increase in diabetes prevalence over 22 years . 
 this mainly results from changes in traditional risk factors , leading to population - wide increases in plasma glucose levels . 
 interventions to control this escalation of diabetes should focus on population - wide strategies .