life in a slum environment can have detrimental effects on residents health status , including manifesting as diminished nutritional status .
sedentary lifestyles are common in urban centers , and unfortunately , this trend does not exclude slum dwellers.1 although undernutrition had been the main focus of interventions in slum dwellings in the past , a major global shift toward lifestyles conducive to obesity has caused overnutrition to become an issue , as well.2 this phenomenon of having both undernourished and overnourished people living side - by - side is sometimes called the double burden of malnutrition , and much attention is being paid in particular to slum dwelling women s vulnerability to this phenomenon .
women are thought to be more economically and nutritionally insecure , and their physical health as mothers is a predictor of the health of offspring . defining population nutritional status epidemiologically is innately problematic .
but body mass index ( bmi ) is a useful first step and is commonly collected in many government - sponsored national health surveys .
the threshold of obesity has been internationally accepted as a bmi of 30 kg / m.3 while body adiposity index ( bai ) and waist circumference are arguably better indices of actual adiposity,4 bmi is still the most commonly used easily applied indices .
indeed , with a large population , bmi is both a noninvasive and time efficient measure.5 several studies68 have already attempted to determine the factors that have the greatest impact on south asian women s bmi .
pregnant women in assam were found to have a lower bmi if the household consisted of five or more individuals or if income was low.6 according to the national family household survey from 1998 to 1999 ( nfhs-2 ) , different administrative states report different average bmis,7 with more developed states , such as punjab , having higher rates of obesity , while less developed states , such as bihar , having higher levels of chronic energy deficiency.7 as well , yadav and krishnan8 found that urbanization itself is a risk factor for a variety of noncommunicable diseases in india , including obesity . with the present study , we analyzed data from the 20052006 indian national family health survey ( nfhs-3)9 to determine the demographic and behavioral factors mostly associated with the bmi of indian women living in slums .
a previous attempt10 to use these same data to explore bmi categorized their outcome into undernutrition , normal , and overnutrition categories , thus limiting statistical interpretations .
in the study described herein , we sought to conduct a more robust multivariate exploration of these same data , controlling for a wider array of putative covariates and retaining the continuous nature of the bmi outcome variable .
we believe that this constitutes the first published study of bmi in modern indian slums that features special attention to residents with tribal status .
a multiple linear regression was applied to data from the nfhs-3 , with demographic and behavioral factors modeled against the continuous outcome of bmi .
the nfhs-3 defined slums based on any of the following criteria : 1 ) based on the designations by the government established by any act including the slum act , 2 ) governmental recognition of the slum regardless of any previous identification , or 3 ) under the criterion of  a compact area of at least 300 population or ~6070 households of poorly built congested tenements , in unhygienic environment usually with inadequate infrastructure and lacking in proper sanitary and drinking water facilities  , which was assessed visually by the surveyor . in this study , we used the slum definition based on the survey supervisor s assessment of slum status based on three criteria mentioned previously .
as well , women who indicated they were currently pregnant were excluded since they provide a skewed relationship between demographic factors and bmi .
putative covariates showing poor univariate association ( p>0.100 ) with bmi were omitted from inclusion in the final regression model , in order to optimize our model s robustness .
ethical approval was received from the research ethics office of the university of ottawa for this study .
written informed consent was deemed not required for this study by the research ethics office of the university of ottawa , because it used only retrospective , anonymized patient data .
the regression model was determined to be significant ( f=9.776 , p0.0001 ) , producing an r of 0.206 . whether the woman was a member of a scheduled tribe
was not found to be significantly associated with changing bmi , but the p - value of that adjusted association was nonetheless quite low ( p=0.051 ) . as
this is a variable of deep policy relevance , it was useful to conduct an exploratory subanalysis of tribal levels unadjusted association with bmi .
results of that analysis showed that tribal women had significantly lower ( unadjusted ) average bmi than did nontribal women ( 20.43 vs 22.02 , p<0.001 ) .
it was further found that those belonging to a tribe were more likely to dwell in maharashtra or andhra pradesh , be in the poorest or poorer wealth index , and to perform manual labor , regardless of bmi ( p<0.001 ) .
the rise in obesity rates in india has also seen a subsequent increase in noncommunicable diseases , including type 2 diabetes mellitus.11 the naturally strong association between obesity ( measured via bmi ) and diabetes in the examined sample may affect the relationships of bmi with the other variables . to explore this possibility , the regression was run again without the diabetes variable included .
there was no change in covariates statistical significance , thus the diabetes variable was included in the final regression and deemed not to be an effect modifier or a confounding influence .
the increasing bmi of slum dwelling women is most significantly and positively associated with the following factors : frequency of watching television ; having diabetes ; increasing age ; higher wealth index ; and living in the states of new delhi , andhra pradesh , and tamil nadu . belonging to a tribe , while not statistically significant in the adjusted model , was an interesting variable in that it showed significant unadjusted association with living in maharashtra or andhra pradesh , doing manual labor , and being in the poorer or poorest wealth index .
our major findings are reflected in the existing literature , which confirm that among low income indians , a sedentary lifestyle , including watching television , is a major contributor to obesity and other noncommunicable diseases.12 it is important to note that the analyzed data are from 2005 to 2006 .
however , these data remain the most comprehensive set describing the entirety of the indian slum dwelling experience and must therefore suffice for the time being .
surprisingly , we did not find a significant adjusted association between education level and bmi ( given that education is associated with career opportunities and therefore wealth ) , though the unadjusted relationship was indeed significant ( p=0.037 ) .
this suggests that other factors may have been mediating the independent relationship between these two factors .
this leads us to believe that having assets and adequate housing ( as measured by the wealth index ) is more influential than educational status alone , however attained .
both education and wealth are dimensions of socioeconomic status , which also include some measurement of social class .
and in india , there is no more profound indicator of social class than caste .
caste classification is long known as an important consideration for doing any sort of population research in india , with hereditary classification of lower ranked individuals associated with a variety of economic , and thus health , disadvantages.13 caste , defined by family lineage , defines a social hierarchy among individuals , often dictating profession , diet , and living conditions .
tribal populations are not part of the formal historic caste structure , but tribal peoples have long faced discrimination similar to that experienced by members of the lowest ranked castes.13 to our knowledge , the present results represent the first attempt to model the influence of tribal status on nutritional health within modern slums . while tribe membership accounts for only a small fraction of the individuals in this data set , tribe populations nonetheless constitute a largely socioeconomically disadvantaged group worthy of policy attention .
the literature is barren with respect to the health status and needs of tribal peoples living in india s urban centers .
their needs represent an important future research direction , given tribal peoples well - documented experiences with marginalization and poverty.14 our main methodological limitation is that presented by challenges in variable coding .
caste is a religious classification system mostly used by hindus,13 but limitedly present in some other religions , as well , including sikhs and buddhists .
however , of the 7952 women examined , only 68.2% were hindu , over 95% identified as belonging to a caste , despite it being an overwhelmingly hindu designation .
it is unclear whether nonhindus reported believing themselves to be part of this hierarchy or whether the question was asked of them poorly .
so - called unidentified slums , which are urban areas with slum - like conditions , which nevertheless do not have the formal designation , have similar , if not worse , conditions than identified slums.1 our sample therefore undersamples indians living in the urban conditions we sought to examine .
it would be problematic to draw comparisons from our sample to nonslum dwellers , given that many of those may in fact experience similar slum - like conditions without the mantle of a formal slum designation .
unidentified slums are known to have similar , if not worse , living conditions than identified slums ; comparatively inferior conditions are related to the fact that unidentified slums are not eligible for publicly funded amenities due to their lack of classification .
this reality serves to keep slum dwellers from unidentified slums , including those who may belong to a tribe , in a lower wealth index compared to slum dwellers from identified slums.15 one clear message arising from these data is that slum dwellers in india are not a homogenous population .
factors such as basic housing and sanitation contribute to the wealth index calculation and are important to examine in slum dwellers because a need for infrastructure improvement is still prevalent .
however , while slum dwellers have largely been characterized as profoundly impoverished , in these data , it was revealed there are slum dwellers belonging to the middle and richer wealth indexes , indicating that certain slum dwellers experience significantly greater economic standing than others .
this is a critical consideration in the development of interventions or for providing resources because slum dweller needs will vary ; some segments of the population may already have significant assets available to them while many others require some form of financial assistance
. it will be important for future research to analyze the economic characteristics of the slum population under study before an appropriate intervention is formulated .
it is important to note that many previous studies have drawn attention to the so - called double burden of under- and overnutrition in india .
slum dwellings , which were historically associated with undernutrition , are now experiencing growing rates of obesity due presumably to the lifestyle associated with increasing urbanization.16,17 thus , slum dwellings , like indian urban centers in general , are experiencing the double burden in lock step with the rest of the country . the extent to which  slum dwelling  may deserve a unique designation that distinguishes such neighborhoods from other urban environments  at least for population health purposes  may be overstated .
while expected factors , such as age , diabetes , and a sedentary lifestyle , are associated with increasing bmi among slum dwelling indian women , the important insight arising from our study is that nutritional health challenges to indian slums may not be dissimilar to challenges experienced by other urban residents , though the experiences of tribal peoples are deserving of more focused attention in future research projects .
 backgroundurbanization is increasing around the world , and in india , this trend has translated into an increase in the size of slum dwellings whose environments are suspected of being associated with poor health outcomes , particularly those relating to women s nutritional status . with this study , we sought to determine the factors associated with indian women s body mass index ( bmi ) in slum environments , with special attention paid to women with tribal status.methodsa multiple linear regression analysis was performed on data from the indian national family health survey ( 20052006 ) , modeling demographic and behavioral factors suspected of being associated with bmi , with additional focus on the measures of social class , specifically caste and tribal status.resultsincreasing bmi is significantly and positively associated with frequency of watching television , having diabetes , age , wealth index , and residency status in the areas of new delhi , andhra pradesh , or tamil nadu.conclusionalthough belonging to a scheduled tribe was not associated with changes in bmi , unadjusted rates suggest that tribal status may be worthy of deeper investigation . among slum dwellers , there is a double burden of undernutrition and overnutrition . 
 therefore , a diverse set of interventions may be required to improve the health outcomes of these women . 
Introduction
Methods
Results
Discussion
Conclusion