Sharif Mahmood | University of Dhaka, Bangladesh (original) (raw)

Papers by Sharif Mahmood

This is an Open Access article distributed under the terms of the Creative Commons At-

This paper presents the application of generalized additive model (GAM) and generalized linear mo... more This paper presents the application of generalized additive model (GAM) and generalized linear model (GLM) as an exploratory tool for analyzing the factors that affect the occurrence of diarrhea of Bangladeshi child. The relation between the factors that are related with occurrence of diarrhea can be obtained by modeling parametric approach (GLM). But in practice the relation is not straight forward and we require elaborate explanations which incline semiparametric regression (GAM). We present a unified approach for analyzing factors affecting diarrhea via GLM and GAM. We applied Akaike's information criterion to select the best model for our data. Our study analyzes nonlinear resolution of covariate not available with traditional parametric models and the results provide some evidence on how to reduce occurrence of diarrhea by improving socio-economic and public health conditions.

The paper presents an investigation of estimating treatment effect using different matching metho... more The paper presents an investigation of estimating treatment effect using different matching methods. The study proposed a new method which is computationally efficient and convenient in implication-'largest caliper matching' and compared the performance with other five popular matching methods by simulation. The bias, empirical standard deviation and the mean square error of the estimates in the simulation are checked under different treatment prevalence and different distributions of covariates. A Monte Carlo simulation study and a real data example are employed to measure the performance of these methods. It is shown that matched samples improve estimation of the population treatment effect in a wide range of settings. It reduces the bias if the data contains the selection on observables and treatment imbalances. Also, findings about the relative performance of the different matching methods are provided to help practitioners determine which method should be used under cer...

The paper presents an investigation of estimating treatment effect using different matching metho... more The paper presents an investigation of estimating treatment effect using different matching methods through Monte Carlo simulation. The study proposed a new method which is computationally efficient and convenient in implication-largest caliper matching and compared the performance with other five popular matching methods. The bias, empirical standard deviation and the mean square error of the estimates in the simulation are checked under different treatment prevalence and different distributions of covariates. It is shown that largest caliper matching improves estimation of the population treatment effect in a wide range of settings compare to other methods. It reduces the bias if the data contains the selection on observables and treatment imbalances. Also, findings about the relative performance of the different matching methods are provided to help practitioners determine which method should be used under certain situations. An application of these methods is implemented on the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT) data and, important demographic and socioeconomic factors that may affect the clinical outcome are also reported in this paper.

Diabetes & Metabolism Journal, 2015

With regard to the paper by Bhowmik et al. (Diabetes Metab J 2013;37:46-53), the statement that t... more With regard to the paper by Bhowmik et al. (Diabetes Metab J 2013;37:46-53), the statement that the protocol was approved by the Norwegian Ethical Committee is incorrect. The authors deeply apologize for the imprecise statement. All the subjects were from Bangladesh and ethical clearance was approved only by the Ethical Committee from Bangladesh. All necessary information was collected from the participants following participant consent. The research was conducted following Declaration of Helsinki.

The present work demonstrates an application of random effects model for analyzing birth interval... more The present work demonstrates an application of random effects model for analyzing birth intervals that are clustered into geographical regions. Observations from the same cluster are assumed to be correlated because usually they share certain unobserved characteristics between them. Ignoring the correlations among the observations may lead to incorrect standard errors of the estimates of parameters of interest. Beside making the comparisons between Cox's proportional hazards model and random effects model for analyzing geographically clustered time-to-event data, important demographic and socioeconomic factors that may affect the length of birth intervals of Bangladeshi women are also reported in this paper.

Journal of Ethnopharmacology

BACKGROUND: To observe changes in the prevalence of type 2 diabetes mellitus (DM) and impaired fa... more BACKGROUND: To observe changes in the prevalence of type 2 diabetes mellitus (DM) and impaired fasting glucose (IFG) and its associated risk factors in a rural Bangladeshi population over a 10-year period.METHODS: Three cross-sectional studies were undertaken in a rural community (aged ≥20 years) in 1999, 2004, and 2009. Structured questionnaires including sociodemographic parameters, anthropometric measurements, blood pressure, and blood glucose values were recorded. DM and IFG were diagnosed using 1999 World Health Organization criteria.RESULTS: Age standardized prevalence of DM increased significantly (P<0.001) from 1999 to 2009 (2.3%, 6.8%, and 7.9% in 1999, 2004, and 2009, respectively). The prevalence of IFG increased significantly (P=0.011) from 4.6% to 5.8% between 1999 and 2004 but then decreased from 5.8% to 5.3% during 2004 to 2009. Significant linear trends were shown in both sexes for general and central obesity as indicated by body mass index, waist circumference, and waist hip ratio (WHR). Increasing age and systolic blood pressure were significant risk factors for DM in all three studies. WHR for males was also significantly associated with the risk of DM in all three studies. WHR for females was only significantly associated with DM in 2009.CONCLUSION: A significant rise in the prevalence of DM was observed in this population over 10 years. This increase was seen in both sexes, and in all age groups. A significant increase in the prevalence of the associated risk factors of general and central obesity was observed in both sexes.

AimsTo evaluate HbA1c as a tool for the diagnosis of diabetes and pre-diabetes (impaired glucose ... more AimsTo evaluate HbA1c as a tool for the diagnosis of diabetes and pre-diabetes (impaired glucose tolerance and/or impaired fasting glucose) and to identify the optimal cut-off values suitable for a Bangladeshi population.To evaluate HbA1c as a tool for the diagnosis of diabetes and pre-diabetes (impaired glucose tolerance and/or impaired fasting glucose) and to identify the optimal cut-off values suitable for a Bangladeshi population.MethodsIn this cross-sectional survey in a rural community, 2293 randomly selected individuals aged ≥ 20 years without prior history of diabetes were included. HbA1c and other clinical covariates necessary for the diagnosis of diabetes were recorded. Diabetes and pre-diabetes were defined according to the World Health Organization 1999 criteria. The receiver operating characteristic curve was used to determine the performance of HbA1c.In this cross-sectional survey in a rural community, 2293 randomly selected individuals aged ≥ 20 years without prior history of diabetes were included. HbA1c and other clinical covariates necessary for the diagnosis of diabetes were recorded. Diabetes and pre-diabetes were defined according to the World Health Organization 1999 criteria. The receiver operating characteristic curve was used to determine the performance of HbA1c.ResultsThe prevalences of diabetes and pre-diabetes were 7.9 and 8.6%, respectively. Based on receiver operating characteristic curve analysis, an HbA1c cut-off value of ≥ 42 mmol/mol (≥ 6.0%) gave an optimal sensitivity of 86.2% and specificity of 93.3%, with an area under the curve of 0.949 to predict diabetes using the oral glucose tolerance test as the gold standard; a cut-off value of ≥ 38 mmol/mol (≥ 5.6%) gave an optimal sensitivity of 68.0% and specificity of 66.4%, with an area under the curve of 0.714 to predict pre-diabetes. In subjects at high risk of diabetes, HbA1c ≥ 42 mmol/mol (≥ 6.0%) showed higher sensitivity than fasting plasma glucose ≥ 7.0 mmol/l, 2-h plasma glucose ≥ 11.1 mmol/l and HbA1c ≥ 48 mmol/mol (≥ 6.5%).The prevalences of diabetes and pre-diabetes were 7.9 and 8.6%, respectively. Based on receiver operating characteristic curve analysis, an HbA1c cut-off value of ≥ 42 mmol/mol (≥ 6.0%) gave an optimal sensitivity of 86.2% and specificity of 93.3%, with an area under the curve of 0.949 to predict diabetes using the oral glucose tolerance test as the gold standard; a cut-off value of ≥ 38 mmol/mol (≥ 5.6%) gave an optimal sensitivity of 68.0% and specificity of 66.4%, with an area under the curve of 0.714 to predict pre-diabetes. In subjects at high risk of diabetes, HbA1c ≥ 42 mmol/mol (≥ 6.0%) showed higher sensitivity than fasting plasma glucose ≥ 7.0 mmol/l, 2-h plasma glucose ≥ 11.1 mmol/l and HbA1c ≥ 48 mmol/mol (≥ 6.5%).ConclusionsAn HbA1c cut-off value of ≥ 42 mmol/mol (≥ 6.0%) was highly sensitive and specific in diagnosing diabetes mellitus. This optimal cut-off level may be suitable as a diagnostic criterion for diabetes in a Bangladeshi population.An HbA1c cut-off value of ≥ 42 mmol/mol (≥ 6.0%) was highly sensitive and specific in diagnosing diabetes mellitus. This optimal cut-off level may be suitable as a diagnostic criterion for diabetes in a Bangladeshi population.

To determine the prevalence of type 2 diabetes (T2DM) and impaired glucose regulation (impaired f... more To determine the prevalence of type 2 diabetes (T2DM) and impaired glucose regulation (impaired fasting glucose [IFG] and impaired glucose tolerance [IGT]) in an urbanizing rural population of Bangladesh and associated cardiometabolic risk indicators and depression. Methods: A total of 2,293 subjects aged ≥20 years in an urbanizing rural Bangladeshi community were investigated. Socio-demographic and anthropometric details, blood pressure, fasting plasma glucose (FPG), 2 hours after 75 g plasma glucose (2hPG), glycosylated hemoglobin, fasting serum insulin and lipid profiles were studied. Presence of depressive symptoms using Montogomery-Asberg Depression Rating Scale was also assessed. Results: The prevalence of IFG, IGT, IFG+IGT, and T2DM were 3.4%, 4.0%, 1.2%, and 7.9%, respectively. The prevalence of T2DM and impaired glucose regulation differed between males and females, but, both increased with age in both sexes. FPG and 2hPG had positive correlation. Employing logistic regression, it was found that increased age, waist to hip ratio, systolic blood pressure, total cholesterol, triglycerides, and depression were independent risk indicators for diabetes. Both insulin resistance and β-cell deficiency were significantly related for causation of diabetes. Among the study population, 26.2% had general obesity, 39.8% central obesity, 15.5% hypertension, 28.7% dyslipidemia, 17.6% family history of diabetes, and 15.3% had depression. Physical inactivity and smoking habits were significantly higher in male. Conclusion: Rising prevalence of diabetes and impaired glucose regulation in this urbanizing rural population exist as a significant but hidden public health problem. Depression and other cardiometabolic risk indicators including obesity, hypertension, and dyslipdemia were also prevalent in this population.

This paper presents the present condition of birth interval in Bangladesh and different demograph... more This paper presents the present condition of birth interval in Bangladesh and different demographic and socio-economic factors that affect the birth interval using product-limit estimate and accelerated failure time regression model. Determination and identification of the factors causing variation in length of birth interval is of great importance for its direct relation to fertility. We have found that mother's education, mother's age and place of residence have a great influence for variation in birth interval. This study demonstrates how the factors affect the parents for having successive children in Bangladesh.

Books by Sharif Mahmood

Survival data are often clustered into groups, such as couples, families, communities, and geogra... more Survival data are often clustered into groups, such as couples, families, communities, and geographical regions. Observations from same cluster usually share certain unobserved characteristics and as a result tend to be correlated. In multivariate proportional hazards model correlations among observations are considered. In analysis if associations among observations are ignored, standard error of the estimates of parameters of interest may be incorrect. The parameters estimates yielded by the multivariate proportional hazards model are very similar to those yielded by the standard hazards model. Present research deals with the extension of the Cox model that allows for heterogeneity due to omitted covariates using frailty (random effect) approach, and there by uses a more general class of mixed-modeling that estimates predictors via parametric and non-parametric regression. In this study, Cox model and multivariate proportional hazards model are used for analyzing birth interval of Bangladesh using Bangladesh Demographic and Health Survey (BDHS, 2004) data. This result of this study indicates that, the unobserved cluster effect has a sizeable impact on birth interval in Bangladesh. Mothers’ education and mothers’ age has a significant effect on birth interval. The most important factor for birth interval is survival status of child. The hazard rate is higher in Sylhet division and lower in Khulna division. This study demonstrate how the factors affect the parents for having successive children in Bangladesh.

Mucoadhisive microcapsules are proposed for the antidiabetic drug glipizide, to obtain controlled... more Mucoadhisive microcapsules are proposed for the antidiabetic drug glipizide, to obtain controlled release. Glipizide microcapsules with a coat consisting of pectin was prepared by employing ionic gelation process and emulsification ionotropic gelation process. The microcapsules were evaluated for flow properties, Carr’s index, hausner ratio, micro encapsulation efficiency, drug release characteristics, surface characteristics; compatibility studies mucoadhesive properties. Pectin is a polysaccharide with a variable molecular weight. In the presence of calcium ions, pectin forms a gel of calcium pectinatethat are more resistant to disruption in the gut than alginate gel. Researchers have formulated oral controlled release products of glipizide by various techniques. Dosage forms that are retained in the stomach would increase the absorption, improve drug efficiency and decrease dose requirements. Thus, an attempt is made in the present investigation to use chitosan as a mucoadhesive polymer and prepare microspheres. The microspheres will be characterized by in-vitro and iv-vivo tests and factorial design will be employed to optimize the variables.

Talks by Sharif Mahmood

This is an Open Access article distributed under the terms of the Creative Commons At-

The paper presents an investigation of estimating treatment effect using different matching metho... more The paper presents an investigation of estimating treatment effect using different matching methods through Monte Carlo simulation. The study proposed a new method which is computationally efficient and convenient in implication-largest caliper matching and compared the performance with other five popular matching methods. The bias, empirical standard deviation and the mean square error of the estimates in the simulation are checked under different treatment prevalence and different distributions of covariates. It is shown that largest caliper matching improves estimation of the population treatment effect in a wide range of settings compare to other methods. It reduces the bias if the data contains the selection on observables and treatment imbalances. Also, findings about the relative performance of the different matching methods are provided to help practitioners determine which method should be used under certain situations. An application of these methods is implemented on the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT) data and, important demographic and socioeconomic factors that may affect the clinical outcome are also reported in this paper.

Diabetes & Metabolism Journal, 2015

Journal of Ethnopharmacology