Body Mass Index Cut-off Associated with Diabetes and Metabolic Abnormality in Indo-Guyanese Adults

Research Article

Austin J Public Health Epidemiol. 2014;1(3): 1013.

Body Mass Index Cut-off Associated with Diabetes and Metabolic Abnormality in Indo-Guyanese Adults

Hosler AS1*and Lu T1

1Department of Epidemiology and Biostatistics, University at Albany School of Public Health, USA

*Corresponding author: Akiko S. Hosler, Department of Epidemiology and Biostatistics, University at Albany School of Public Health, GEC 147 One University Place, Rensselaer, NY 12144, USA

Received: October 07, 2014; Accepted: November 05, 2014; Published: November 07, 2014


Aim: To identify body mass index (BMI) cut-offs associated with diabetes and glucose abnormality (diabetes, pre-diabetes and borderline diabetes combined) among Indo-Guyanese adults in a U.S. urban community.

Methods: Cross-sectional health survey data of Indo-Guyanese adults in Schenectady, NY were analyzed. Diagnosed diabetes and glucose abnormality were verified for its reporting accuracy and used as the outcome variables. Unadjusted and adjusted Poisson regression models were fitted to estimate the prevalence ratio (PR) by BMI cut-offs of 1.0 kg/m2 increment. The adjusted models included age, sex, high blood pressure, high blood cholesterol, and family history of diabetes.

Results: The analysis sample (n=316) was 54.4% female with a mean age of 45.1 years. BMIs ranged from 16.9 kg/m2 to 45.2 kg/m2. Ninety-five (30.1%) and 15 (4.7%) participants reported diabetes and pre-diabetes/borderline diabetes respectively. PR for diabetes was highest at BMI 23.0 kg/m2 (unadjusted PR 3.34, 95% CI 1.68, 6.63; adjusted PR 1.83, 95% CI 1.01, 3.33). Similarly, PR for glucose abnormality was highest at BMI 23.0 kg/m2 (unadjusted PR 3.90, 95% CI 1.97, 7.71; adjusted PR 2.28. 95% CI 1.24, 4.17).

Conclusion: This study demonstrated that both diabetes and glucose abnormality were associated with BMI of 23.0 kg/m2 in Indo-Guyanese adults. These results were consistent with previously reported optimal BMI cut-offs for diabetes and pre-diabetes among various South Asian populations. Public health and medical professionals should be aware of the elevated likelihood of having diabetes or pre-diabetes among Indo-Guyanese adults whose BMIs are below the overweight range.

Keywords: Indo-Guyanese; Diabetes risks; Glucose abnormality; Body mass index; Prevalence ratio; Cut-off points


BMI: Body Mass Index; CI: Confidence Interval; PABAK: Prevalence-Adjusted Bias-Adjusted Kappa; PR: Prevalence Ratio; SD: Standard Deviation; WHO: World Health Organization


Body mass index (BMI) has been widely used to assess risks for obesity-related chronic diseases including type 2 diabetes. BMI of 25kg/m2, which defines the lower limit of the overweight range by the WHO criteria [1], is the most commonly recognized cut-off to identify elevated diabetes risk in U.S. adults [2]. Epidemiologic studies have demonstrated, however, an appropriate BMI cut-off for diabetes can vary by race and ethnicity [3,4]. Experts explain that this is largely because the associations between BMI, proportion of body fat, and body fat distribution pattern differ across populations [3]. For South Asians, evidence suggests that diabetes is associated with a BMI between 22.0 kg/m2 and 24.0 kg/m2 [4-8].

It has not been investigated whether a BMI cut-off lower than 25 kg/m2 is feasible to indicate elevated likelihood of having diabetes in Indo-Guyanese population in the U.S. The Indo-Guyanese is one of the largest new immigrant groups in cities in the northeast U.S. [9]. They migrated from the English-speaking South American country of Guyana, but most of them can trace their ancestry to the 19th century India, and they remain phenotypically and genetically South Asian due to a low rate of intermarriage [10]. This unique group is largely medically underserved, and their health conditions are not well investigated. Recently published studies reported a highly elevated prevalence of diabetes and its complications in Indo-Guyanese adults, and also found that BMI for the Indo-Guyanese with diabetes was significantly lower compared to that for other racial/ethnic groups with diabetes [11,12].

Identifying individuals likely to be affected by diabetes using a simple indicator such as BMI is an important step toward reducing the burden of diabetes in Indo-Guyanese communities. Identification of individuals with pre-diabetes, a precursor to type 2 diabetes is particularly important, given that lifestyle and pharmacological interventions can effectively stop or delay the progression into diabetes [13]. The objective of this study is to identify the BMI cut-off that is associated with diabetes and more inclusive glucose abnormality (diabetes, pre-diabetes and borderline diabetes combined) among Indo-Guyanese adults in a U.S. urban community.


Data source

Data for this study were obtained from a cross-sectional health survey of adults conducted in Schenectady, New York. Eligibility of respondents was being at least 18 years of age and a current resident of Schenectady. Using venue-based quota sampling technique, respondents were recruited at 36 community locations and events. A small number of respondents were also recruited through referrals from community members and door-to-door visits. The age-sex distribution of respondents was closely monitored, and recruitment strategies were adjusted to ensure that the sample had a similar age-sex distribution of the city's adult population.

Respondents filled out a 42-item health questionnaire written at a 6th grade level in English. Trained members of the research team provided assistance in completing the questionnaire, if requested by the respondent. The survey questionnaire was pilot-tested with a sample of Schenectady residents (n=12) and found perfect test-retest agreement (prevalence-adjusted bias-adjusted kappa or PABAK>1.0) in 9 key variables including age, sex, diagnosis of diabetes, and family history of diabetes, and excellent agreement (PABAK>0.8) in all other health-related variables. A total of 792 respondents were in the original data set. This study used the unweighted subset of the survey data containing only respondents with Indo-Guyanese ethnicity (N=333). The institutional review boards of Ellis Hospital in Schenectady and University at Albany reviewed and approved the human subject protection protocol.


Two questions "Has a health professional ever told you that you have diabetes?" and "Has a health professional ever told you that you have pre-diabetes or borderline diabetes?" were used to derive diabetes (yes to the first question) and abnormal blood glucose (yes to any of the two). BMI was computed from body weight in pounds and height without shoes in inches. Seventeen individuals provided no body weight and/or height information so their BMIs were unavailable. Since no significant differences (P<0.01) in age, sex, and diagnosis of diabetes were found between the respondents with and without BMI, the latter group was excluded from analysis. Age, sex, diagnoses of high blood pressure and high blood cholesterol (ever told by a health professional), and family history of diabetes (specific to mother, father, sisters or brothers) were also reported by respondents. The sample size of the analysis data set was 316.

Assessing accuracy of self-reported diabetes status

Because the Indo-Guyanese are mostly medically underserved, some individuals may not be aware of their elevated glucose status. An auxiliary study was conducted to examine whether those who reported not having diabetes or pre-diabetes were truly so. Data from a free community glucose screening event held in Schenectady were linked to the survey data, and found 13 matched participants. In this screening event, individuals who had been diagnosed with diabetes were not invited. The American Diabetes Association's guidelines were used to determine diabetes risks into 3 categories: Low risk (non-fasting plasma glucose < 140 mg/dl), medium risk (140 mg/dl - 199 mg/dl), and high risk (≥ 200 mg/dl) [2]. All of those who had reported not having been diagnosed with diabetes, pre-diabetes, or borderline diabetes in the survey (N=9) were in the low risk group (range: 89 mg/ dl to 128 mg/dl), with a mean of 107.6 mg/dl (SD 11.5). Individuals who had reported having pre-diabetes or borderline diabetes (N=4) had non-fasting plasma glucose values all above 140 mg/dl (range: 143 mg/dl to 279 mg/dl), with a mean of 210.3mg/dl (SD 57.8). The pre-diabetes group's mean glucose value was significantly higher (p<0.01) than the disease-free group's mean glucose value. These results suggested accuracy of self-reported disease-free status in this population. In addition, respondents who reported having been diagnosed with diabetes were probed for their diabetes-related health conditions and medical care in the survey, and all their responses were consistent with their diseased status.


Diabetes is relatively common in the Indo-Guyanese, affecting about a third of the adult population [11,12]. When the outcome measure is not uncommon, the odds ratio overestimates the effect of exposure [14]. As a better alternative, Poisson regression models were fitted to directly estimate the prevalence ratio of diabetes and glucose abnormality [15]. First, unadjusted prevalence, prevalence ratio, and its 95% confidence intervals were obtained for BMI cut-offs of every 1 kg/m2 increment from 21.0 kg/m2 to 31.0 kg/m2, where there were at least 10 respondents for each BMI category. Then, adjusted Poisson regression models were analyzed for BMI cut-offs for 21.0 kg/m2 to 28.0 kg/m2. BMI of 28.0 kg/m2 was the threshold at which the confidence intervals of unadjusted prevalence ratio were no longer entirely above the null. Covariates in the adjusted models were age (in years), sex, and three commonly assessed clinical variables that had significant (P<0.01) bivariate associations with BMI and/ or glucose abnormality, including high blood pressure, high blood cholesterol, and family history of diabetes. The prevalence ratio and 95% confidence intervals were reported. All analyses were conducted using SAS ver. 9.3 (SAS Institute, Inc. Cary, North Carolina).


Characteristics of respondents in the sample are summarized in Table 1. The ages of respondents ranged from 18 to 82 years, with a mean of 45.1 years (SD 14.4). Slightly more than a half of respondents (54.4%) were female, and great majorities (97.2%) were born in Guyana. BMI had a range of 16.9 kg/m2 to 45.2 kg/m2, and a mean of 26.7 kg/m2 (SD 4.1). Gender difference in BMI was very small and non-significant (P>0.01), with a mean of 26.9 kg/m2 (SD 4.1) for females and 26.6 kg/m2 (SD 4.0) for males. Approximately two thirds of respondents had a BMI higher than 25.0 kg/m2. Ninety-five individuals (30.1%) reported diagnosed diabetes, and additional 15 (4.7%) reported diagnosed pre-diabetes or borderline diabetes. Together, 34.8% of the sample was classified as having glucose abnormality.

Citation: Hosler AS and Lu T. Body Mass Index Cut-off Associated with Diabetes and Metabolic Abnormality in Indo-Guyanese Adults. Austin J Public Health Epidemiol. 2014;1(3): 1013. ISSN 2381-9014