Diabetes and other disorders of glycemia in a rural South African community: prevalence and associated risk factors

OBJECTIVE—The purpose of this study was to determine the prevalence of diabetes, impaired glucose tolerance (IGT), impaired fasting glycemia (IFG), and associated risk factors in a rural South African black community.RESEARCH DESIGN AND METHODS—This was a cross-sectional survey conducted by random cluster sampling of adults aged >15 years. Participants had a 75-g oral glucose tolerance test using the 1998 World Health Organization criteria for disorders of glycemia.RESULTS—Of 1,300 subjects selected, 1,025 subjects (815 women) participated (response rate 78.9%). The overall age-adjusted prevalence of diabetes was 3.9%, IGT 4.8%, and IFG 1.5%. The prevalence was similar in men and women for diabetes (men 3.5%; women 3.9%) and IGT (men 4.6%; women 4.7%) but higher in men for IFG (men 4.0%; women 0.8%). The prevalence of diabetes and IGT increased with age both in men and women, with peak prevalence in the 55- to 64-year age-group for diabetes and in the ≥65-year age-group for IGT. Of the cases of diabetes, 84.8% were discovered during the survey. In multivariate analysis, the significant independent risk factors associated with diabetes included family history (odds ratio 3.5), alcohol ingestion (2.8), waist circumference (1.1), systolic blood pressure (1.0), serum triglycerides (2.3), and total cholesterol (1.8); hip circumference was protective (0.9).CONCLUSIONS—There is a moderate prevalence of diabetes and a high prevalence of total disorders of glycemia, which suggests that this community, unlike other rural communities in Africa, is well into an epidemic of glucose intolerance. There is a low proportion of known diabetes and a significant association with potentially modifiable risk factors.Over the past few decades, type 2 diabetes has emerged as an important medical problem in sub-Saharan Africa (SSA). Until the 1980s, the few reported studies indicated a low prevalence, i.e., between 0 and 1.0% (1,2).From recent estimates of the International Diabetes Federation, the largest increases in prevalence of diabetes are expected to occur in developing regions of the world, including Africa. For Africa, the regional prevalence of diabetes is projected to increase from 3.1% in 2007 to 3.5% in 2025, with a corresponding increase in numbers: from 10.4 to 18.7 million. The report also highlighted the paucity of prevalence data for Africa (3).Much of the available, albeit limited, data on the epidemiology of diabetes in Africa are those based on 1985 World Health Organization (WHO) criteria (4). These studies show a variable prevalence of diabetes, with low rates (<3%) in both urban and rural communities in West and East Africa, whereas moderate rates (3–10%) are reported in periurban and urban communities in South Africa, comparable with rates in developed countries. The moderate to high prevalence of IGT, especially in populations with low diabetes prevalence, is suggestive of the early stage of a diabetes epidemic (2,3,5).Where examined, diabetes prevalence is higher in urban than in rural communities in the same country and lower in the indigenous African population than in migrant Asian or mixed-ancestry communities. There is evidence for significant association with age, family history of diabetes, adiposity, urbanization, and high rates of IGT with low diabetes prevalence and a low proportion of known diabetes (2,5).The three reported studies from indigenous population groups in South Africa have shown moderate diabetes prevalence varying from 5.3 to 8.0% (6–8). The only reported studies from Africa using current revised American Diabetes Association (ADA) (9) and WHO (10) criteria are those from Tanzania (11) and Ghana (12). To date, there are no studies reported in rural communities in South Africa and none, either urban or rural, using the current criteria. This study was undertaken to determine the prevalence of diabetes and associated risk factors in a rural South African community of Zulu descent using 1998 WHO criteria for disorders of glycemia.     

A class of repeated measures concordance correlation coefficients

The repeated measures concordance correlation coefficient was proposed for measuring agreement between two raters or two methods of measuring a response in the presence of repeated measurements (King et al., 2007). This paper proposes a class of repeated measures concordance correlation coefficients that are appropriate for both continuous and categorical data. We illustrate the methodology with examples comparing (1) 1-hour vs. 2-hour blood draws for measuring cortisol in an asthma clinical trial, (2) two measurements of percentage body fat, from skinfold calipers and dual energy x-ray absorptiometry, and (3) two binary measures of quality of health from an asthma clinical trial.     

Treatment of hypertension and diabetes mellitus in patients with chronic kidney disease: a review

Hypertension and diabetes mellitus are the two leading causes of chronic kidney disease (CKD). The purpose of this paper is to provide an overview of the present pharmacologic and adverse events involved in the treatment of hypertension and diabetes mellitus in patients with CKD. Proper management of hypertension and diabetes mellitus, a common co-morbidity associated with CKD, would slow the progression of kidney disease and reduce healthcare expenditures. Awareness of potential side effects due to the medications or renal insufficiency could prevent unnecessary harm to the patient and provide cost-containment. Active involvement of all healthcare team members can reduce progression of CKD and improve quality of life outcomes in CKD patients.     

Prevalence of Ehrlichia, Borrelia, and Rickettsial agents in Amblyomma americanum (Acari: Ixodidae) collected from nine states

Ambyomma americanum (L.) (Acari: Ixodidae) is an aggressive tick that feeds on humans during all postembryonic life stages. In many regions of the United States, it is the tick most commonly found attached to humans. Public health interest has grown recently, due to the recognition of new human pathogens transmitted by A. americanum and the expanding distribution of the tick. A. americanum is a vector of several bacteria pathogenic to humans. Ehrlichia chaffeensis and Ehrlichia ewingii cause moderate-to-severe febrile illness. "Rickettsia amblyommii," a member of the spotted fever group Rickettsia, also has recently been implicated as a possible human pathogen based on serologic evidence from persons recovering from illness after a tick bite. We have determined the prevalence of infection of Ehrlichia chaffeensis, E. ewingii, "Borrelia lonestari", and R. amblyommii within A. americanum ticks from 29 sites in nine states. Overall infection prevalences were 4.7% for E. chaffeensis (range, 0-27%), 3.5% for E. ewingii (range, 0-18.6%), 2.5% for B. lonestari (range, 0-12.2%), and 41.2% for R. amblyommii (range, 0-84.0%). In addition, 87 ticks (4.3%) were infected with two or more bacteria. This report documents new distribution records for E. ewingii, B. lonestari, and R. amblyommii and underscores the nonhomogeneous distribution of pathogen foci of infection. Additional surveillance throughout the range ofA. americanum is warranted to increase physician and public awareness of the risk of disease to humans from exposure to the agents transmitted by this tick.     

Polymorphisms in the novel gene acyloxyacyl hydroxylase (AOAH) are associated with asthma and associated phenotypes

BACKGROUND: The gene encoding acyloxyacyl hydroxylase (AOAH), an enzyme that hydrolyzes secondary fatty acyl chains of LPS, is localized on chromosome 7p14-p12, where evidence for linkage to total IgE (tIgE) concentrations and asthma has been previously reported. OBJECTIVE: We hypothesized that variants in AOAH are associated with asthma and related phenotypes. Because both AOAH and soluble CD14 respond to LPS, we tested for gene-gene interaction. METHODS: We investigated the association between 28 single nucleotide polymorphisms throughout the AOAH gene and asthma, concentrations of tIgE, the ratio of IL-13/IFN-gamma, and soluble CD14 levels among 125 African Caribbean, multiplex asthmatic pedigrees (n = 834). Real-time PCR was used to assess whether AOAH cDNA expression differed with AOAH genotype. RESULTS: Significant effects were observed for all 4 phenotypes and AOAH markers in 3 distinct regions (promoter, introns 1-6, and the intron 12/exon 13 boundary/intron 13 region) by means of single-marker and haplotype analyses, with the strongest evidence for a 2-single-nucleotide-polymorphism haplotype and log[tIgE] (P = .006). There was no difference in AOAH expression levels by AOAH genotype for any of the markers. Comparing genotypic distributions at both the AOAH marker rs2727831 and CD14(-260)C >T raises the possibility of gene-gene interaction (P = .006-.036). CONCLUSION: Our results indicate that polymorphisms in markers within the AOAH gene are associated with risk of asthma and associated quantitative traits (IgE and cytokine levels) among asthmatic subjects and their families in Barbados, and there is an interactive effect on tIgE and asthma concentrations between an AOAH marker and the functional CD14(-260)C >T polymorphism. CLINICAL IMPLICATIONS: AOAH is a novel innate immunity candidate gene associated with asthma and related phenotypes in an African ancestry population.