Neighborhood clustering of non-communicable diseases: results from a community-based study in Northern Tanzania

Socio-environmental predictors of diabetes incidence disparities in Tanzania mainland: a comparison of regression models for count data

BACKGROUND

Diabetes is one of the top four non-communicable diseases that cause death and illness to many people around the world. This study aims to use an efficient count data model to estimate socio-environmental factors associated with diabetes incidences in Tanzania mainland, addressing lack of evidence on the efficient count data model for estimating factors associated with disease incidences disparities.

METHODS

This study analyzed diabetes counts in 184 Tanzania mainland councils collected in 2020. The study applied generalized Poisson, negative binomial, and Poisson count data models and evaluated their adequacy using information criteria and Pearson chi-square values.

RESULTS

The data were over-dispersed, as evidenced by the mean and variance values and the positively skewed histograms. The results revealed uneven distribution of diabetes incidence across geographical locations, with northern and urban councils having more cases. Factors like population, GDP, and hospital numbers were associated with diabetes counts. The GP model performed better than NB and Poisson models.

CONCLUSION

The occurrence of diabetes can be attributed to geographical locations. To address this public health issue, environmental interventions can be implemented. Additionally, the generalized Poisson model is an effective tool for analyzing health information system count data across different population subgroups.

The relationship between climate change, globalization and non-communicable diseases in Africa: A systematic review

Climate change and non-communicable diseases (NCDs) are considered the 21st Century's major health and development challenges. Both pose a disproportionate burden on low- and middle-income countries that are unprepared to cope with their synergistic effects. These two challenges pose risks for achieving many of the sustainable development goals (SDGs) and are both impacted by globalization through different pathways. While there are important insights on how climate change and or globalization impact NCDs in the general literature, comprehensive research that explores the influence of climate change and or globalization on NCDs is limited, particularly in the context of Africa. This review documents the pathways through which climate change and or globalization influence NCDs in Africa. We conducted a comprehensive literature search in eight electronic databases-Web of Science, PubMed, Scopus, Global Health Library, Science Direct, Medline, ProQuest, and Google Scholar. A total of 13864 studies were identified. Studies that were identified from more than one of the databases were automatically removed as duplicates (n = 9649). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a total of 27 studies were eventually included in the final review. We found that the impacts of climate change and or globalization on NCDs act through three potential pathways: reduction in food production and nutrition, urbanization and transformation of food systems. Our review contributes to the existing literature by providing insights into the impact of climate change and or globalization on human health. We believe that our findings will help enlighten policy makers working on these pathways to facilitate the development of effective policy and public health interventions to mitigate the effects of climate change and globalization on the rising burden of NCDs and goal 3 of the SDG, in particular.

Intracluster correlation estimates from a World Health Organisation STEPwise approach to surveillance (STEPS) survey for cardiovascular risk factors in Vellore, Tamil Nadu, India

OBJECTIVES

Most World Health Organisation (WHO) STEPS surveys use cluster sampling to assess the prevalence of risk factors for non-communicable diseases (NCDs) for which design effects need to be estimated using intracluster correlation (ICCs) coefficients, for sample size calculation. Although there are many reports of risk factor surveys reported from developing countries, there are very few reports of ICCs for risk factors for NCDs, which can inform planning the appropriate sample size needed for such surveys. This study reports the ICCs for NCD risk factors, obtained from a WHO STEPS survey conducted in Vellore district, in the state of Tamil Nadu, South India.

STUDY DESIGN

Cross-sectional study.

METHODS

A cross-sectional study was carried out in 48 urban clusters (wards) and nine rural clusters (villages) between 2011 and 2012, using the WHO STEPS methodology for assessing behavioural, anthropometric, physical and biochemical risk factors. The ICC estimates for various risk factors were obtained using loneway and xtmelogit commands using STATA to study clustering of risk factors.

RESULTS

The number of respondents was 6196 adults aged 30-64 years. The median ICC of cardiovascular risk factors in the urban area was 0.046, while it was 0.064 in the rural area. Clustering was higher for behavioural risk factors such as physical activity (ICC: 0.179 rural, 0.049 urban) and fruit and vegetable intake (ICC: 0.105 rural, 0.091 urban) as compared with physical risk factors (ICCs for hypertension: 0.044 rural, 0.006 urban; body mass index: 0.046 rural, 0.041 urban) and biochemical outcomes such as fasting plasma glucose (ICC: 0.017 rural, 0.027 urban).

CONCLUSIONS

This study provides estimates of ICCs for cardiovascular risk factors from Vellore, South India, as such data have not been reported from WHO STEPS surveys in India or neighbouring countries. Such estimates of ICCs if reported from various WHO STEPS being carried out across the country can contribute to better planning of epidemiological surveys. Clustering of behavioural risk factors at village/ward level as seen in this study points to the need for community-based interventions for health promotion, as spatial clustering influences behaviour, which in turn affects chronic disease outcomes.

Prevalence of CKD, Diabetes, and Hypertension in Rural Tanzania

INTRODUCTION

Chronic kidney disease (CKD), diabetes, and hypertension play a disproportionate role in the growing public health challenge posed by noncommunicable diseases (NCDs) in East Africa. The impact of these NCDs may pose the greatest challenge in rural areas with limited screening and treatment facilities, although precise prevalence estimates of these conditions in rural Tanzania are lacking.

METHODS

The prevalence of CKD, diabetes, and hypertension, were estimated from a probability sample of adults (n = 739) residing in 2 communities within Kisarawe, a rural district of Tanzania. Following consent, participants were studied in their homes. Random point-of-care (POC) measures of glycosylated hemoglobin and blood pressure, were obtained. Serum creatinine, drawn at the POC and measured at Muhimbili National University, was used to calculate estimated glomerular filtration rate with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.

RESULTS

The median age was 35 years (interquartile range 25-45 years). Overall the pooled prevalence for CKD stages III, IV, and V was 12.4% (95% confidence interval [CI] = 10.2-14.8). Surprisingly, the prevalence of CKD stage V (3.0%; 95% CI = 2.1-4.4) was high among the youngest age group (18-36 years). The prevalence estimates for prehypertension and hypertension were 38.0% (95% CI = 34.6-41.5) and 19.9% (95% CI = 17.1-22.9), respectively. The prevalence estimates for prediabetes and diabetes were 25.7% (95% CI = 22.6-29.1) and 14.8% (95% CI = 12.4-17.6), respectively.

CONCLUSION

Although this pilot study had a relatively small sample size, the prevalence estimates for CKD, diabetes, and hypertension were higher than we expected based on previous estimates from Tanzania. CKD was not significantly associated with diabetes or hypertension, suggesting the possibility of an alternative causality.

Built environmental characteristics and diabetes: a systematic review and meta-analysis

BACKGROUND

The built environment influences behaviour, like physical activity, diet and sleep, which affects the risk of type 2 diabetes mellitus (T2DM). This study systematically reviewed and meta-analysed evidence on the association between built environmental characteristics related to lifestyle behaviour and T2DM risk/prevalence, worldwide.

METHODS

We systematically searched PubMed, EMBASE.com and Web of Science from their inception to 6 June 2017. Studies were included with adult populations (>18 years), T2DM or glycaemic markers as outcomes, and physical activity and/or food environment and/or residential noise as independent variables. We excluded studies of specific subsamples of the population, that focused on built environmental characteristics that directly affect the cardiovascular system, that performed prediction analyses and that do not report original research. Data appraisal and extraction were based on published reports (PROSPERO-ID: CRD42016035663).

RESULTS

From 11,279 studies, 109 were eligible and 40 were meta-analysed. Living in an urban residence was associated with higher T2DM risk/prevalence (n = 19, odds ratio (OR) = 1.40; 95% CI, 1.2-1.6; I² = 83%) compared to living in a rural residence. Higher neighbourhood walkability was associated with lower T2DM risk/prevalence (n = 8, OR = 0.79; 95% CI, 0.7-0.9; I² = 92%) and more green space tended to be associated with lower T2DM risk/prevalence (n = 6, OR = 0.90; 95% CI, 0.8-1.0; I² = 95%). No convincing evidence was found of an association between food environment with T2DM risk/prevalence.

CONCLUSIONS

An important strength of the study was the comprehensive overview of the literature, but our study was limited by the conclusion of mainly cross-sectional studies. In addition to other positive consequences of walkability and access to green space, these environmental characteristics may also contribute to T2DM prevention. These results may be relevant for infrastructure planning.

Prevalence and burden of chronic kidney disease among the general population and high-risk groups in Africa: a systematic review

OBJECTIVES

While increasing attention is paid to the rising prevalence of chronic diseases in Africa, there is little focus on chronic kidney disease (CKD). This systematic review assesses CKD burden among the general population and high-risk groups on the entire African continent.

DESIGN, SETTING AND PARTICIPANTS

We searched Medline and PubMed databases for articles published between 1 January 1995 and 7 April 2017 by sensitive search strategies focusing on CKD surveys at the community level and high-risk groups. In total, 7918 references were evaluated, of which 7766 articles were excluded because they did not meet the inclusion criteria. Thus, 152 studies were included in the final analysis.

OUTCOME MEASUREMENT

The prevalence of CKD in each study group was expressed as a range and pooled prevalence rate of CKD was calculated as a point estimate and 95% CI. No meta-analysis was done. Data were presented for different populations.

RESULTS

In the community-level studies, based on available medium-quality and high-quality studies, the prevalence of CKD ranged from 2% to 41% (pooled prevalence: 10.1%; 95% CI 9.8% to 10.5%). The prevalence of CKD in the high-risk groups ranged from 1% to 46% (pooled prevalence: 5.6%; 95% CI 5.4% to 5.8%) in patients with HIV (based on available medium-quality and high-quality studies), 11%-90% (pooled prevalence: 24.7%; 95% CI 23.6% to 25.7%) in patients with diabetes (based on all available studies which are of low quality except four of medium quality) and 13%-51% (pooled prevalence: 34.5%; 95 % CI 34.04% to 36%) in patients with hypertension (based on all available studies which are of low quality except two of medium quality).

CONCLUSION

In Africa, CKD is a public health problem, mainly attributed to high-risk conditions as hypertension and diabetes. The poor data quality restricts the validity of the findings and draws the attention to the importance of designing future robust studies.

Epidemiology of hypertension in Northern Tanzania: a community-based mixed-methods study

INTRODUCTION

Sub-Saharan Africa is particularly vulnerable to the growing global burden of hypertension, but epidemiological studies are limited and barriers to optimal management are poorly understood. Therefore, we undertook a community-based mixed-methods study in Tanzania to investigate the epidemiology of hypertension and barriers to care.

METHODS

In Northern Tanzania, between December 2013 and June 2015, we conducted a mixed-methods study, including a cross-sectional household epidemiological survey and qualitative sessions of focus groups and in-depth interviews. For the survey, we assessed for hypertension, defined as a single blood pressure ≥160/100 mm Hg, a two-time average of ≥140/90 mm Hg or current use of antihypertensive medications. To investigate relationships with potential risk factors, we used adjusted generalised linear models. Uncontrolled hypertension was defined as a two-time average measurement of ≥160/100 mm Hg irrespective of treatment status. Hypertension awareness was defined as a self-reported disease history in a participant with confirmed hypertension. To explore barriers to care, we identified emerging themes using an inductive approach within the framework method.

RESULTS

We enrolled 481 adults (median age 45 years) from 346 households, including 123 men (25.6%) and 358 women (74.4%). Overall, the prevalence of hypertension was 28.0% (95% CI 19.4% to 38.7%), which was independently associated with age >60 years (prevalence risk ratio (PRR) 4.68; 95% CI 2.25 to 9.74) and alcohol use (PRR 1.72; 95% CI 1.15 to 2.58). Traditional medicine use was inversely associated with hypertension (PRR 0.37; 95% CI 0.26 to 0.54). Nearly half (48.3%) of the participants were aware of their disease, but almost all (95.3%) had uncontrolled hypertension. In the qualitative sessions, we identified barriers to optimal care, including poor point-of-care communication, poor understanding of hypertension and structural barriers such as long wait times and undertrained providers.

CONCLUSIONS

In Northern Tanzania, the burden of hypertensive disease is substantial, and optimal hypertension control is rare. Transdisciplinary strategies sensitive to local practices should be explored to facilitate early diagnosis and sustained care delivery.

APOL1 risk alleles among individuals with CKD in Northern Tanzania: A pilot study

INTRODUCTION

In sub-Saharan Africa, approximately 100 million people have CKD, yet genetic risk factors are not well-understood. Despite the potential importance of understanding APOL1 risk allele status among individuals with CKD, little genetic research has been conducted. Therefore, we conducted a pilot study evaluating the feasibility of and willingness to participate in genetic research on kidney disease, and we estimated APOL1 risk allele frequencies among individuals with CKD.

METHODS

In 2014, we conducted a community-based field study evaluating CKD epidemiology in northern Tanzania. We assessed for CKD using urine albumin and serum creatinine to estimate GFR. We invited participants with CKD to enroll in an additional genetic study. We obtained dried-blood spots on filter cards, from which we extracted DNA using sterile punch biopsies. We genotyped for two single nucleotide polymorphisms (SNPs) defining the APOL1 G1 risk allele and an insertion/deletion polymorphism defining the G2 risk allele. Genotyping was performed in duplicate.

RESULTS

We enrolled 481 participant, 57 (12%) of whom had CKD. Among these, enrollment for genotyping was high (n = 48; 84%). We extracted a median of 19.4 ng of DNA from each dried-blood spot sample, and we genotyped the two APOL1 G1 SNPs and the APOL1 G2 polymorphism. Genotyping quality was high, with all duplicated samples showing perfect concordance. The frequency of APOL1 risk variants ranged from 7.0% to 11.0%, which was similar to previously-reported frequencies from the general population of northern Tanzania (p>0.2).

DISCUSSION

In individuals with CKD from northern Tanzania, we demonstrated feasibility of genotyping APOL1 risk alleles. We successfully genotyped three risk variants from DNA extracted from filter cards, and we demonstrated a high enrollment for participation. In this population, more extensive genetic studies of kidney disease may be well-received and will be feasible.

Kidney disease in Uganda: a community based study

Background

Chronic kidney disease (CKD) is a major cause of morbidity and mortality in Sub-Saharan Africa (SSA). The majority of studies on CKD in SSA have been conducted among HIV-infected populations and mainly from large health facilities. We determined the prevalence of CKD and its predictors among populations in communities in central Uganda.

Methods

A cross-sectional study was conducted in Wakiso district using multi-stage sampling. Data was collected on age, sex, socio-economic status, history of alcohol intake, diabetes mellitus, hypertension and smoking. Measurement of blood pressure, weight and height to determine body mass index (BMI) and investigations including HIV testing, fasting blood sugar, creatinine and urinalysis were conducted. Logistic regression was used to estimate the strength of the association between variables and the presence of CKD estimated using the Cockcroft Gault formula.

Results

A total of 955 participants aged 18–87 years were enrolled into the study. The median age was 31 years (Interquartile range 24–42) and majority (67%) were female. Up to 21.4% (204/955) had abnormal renal function with CKD stage 1 in 6.2% (59/955), stage 2 in 12.7% (121/955), stage 3 in 2.4% (23/955), CKD stage 4 in 0% and CKD stage 5 in 0.1% (1/995). Female gender OR 1.8 (95% Confidence Interval [CI] 1.2–2.8), age >30 years OR 2.2(95% CI 1.2–3.8) and high social economic status OR 2.1 (95% CI 1.3–3.6) were associated with increased risk of CKD while BMI > 25Kg/m² was protective against CKD OR 0.1 (95% CI 0.04–0.2). Traditional risk factors such as HIV-infection, diabetes mellitus, smoking and alcohol intake were not found to be significantly associated with CKD.

Conclusion

We found a high prevalence of kidney disease in central Uganda. Interestingly the traditional risk factors associated with CKD previously documented, were not associated with CKD.