Browsing by Subject "Smoking habits"
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- ItemOpen AccessThe association between childhood environmental exposures and the subsequent development of Crohn's Disease in the Western Cape, South Africa(Public Library of Science, 2014) Basson, Abigail; Swart, Rina; Jordaan, Esme; Mazinu, Mikateko; Watermeyer, GillianBACKGROUND: Environmental factors during childhood are thought to play a role in the aetiolgy of Crohn's Disease (CD). However the association between age at time of exposure and the subsequent development of CD in South Africa is unknown. METHODS: A case control study of all consecutive CD patients seen at 2 large inflammatory bowel disease (IBD) referral centers in the Western Cape, South Africa between September 2011 and January 2013 was performed. Numerous environmental exposures during 3 age intervals; 0-5, 6-10 and 11-18 years were extracted using an investigator administered questionnaire. An agreement analysis was performed to determine the reliability of questionnaire data for all the relevant variables. RESULTS: This study included 194 CD patients and 213 controls. On multiple logistic regression analysis, a number of childhood environmental exposures during the 3 age interval were significantly associated with the risk of developing CD. During the age interval 6-10 years, never having had consumed unpasteurized milk (OR = 5.84; 95% CI, 2.73-13.53) and never having a donkey, horse, sheep or cow on the property (OR = 2.48; 95% CI, 1.09-5.98) significantly increased the risk of developing future CD. During the age interval 11-18 years, an independent risk-association was identified for; never having consumed unpasteurized milk (OR = 2.60; 95% CI, 1.17-6.10) and second-hand cigarette smoke exposure (OR = 1.93; 95% CI, 1.13-3.35). CONCLUSION: This study demonstrates that both limited microbial exposures and exposure to second-hand cigarette smoke during childhood is associated with future development of CD.
- ItemOpen AccessThe Association between Race and Crohn's Disease Phenotype in the Western Cape Population of South Africa, Defined by the Montreal Classification System(Public Library of Science, 2014) Basson, Abigail; Swart, Rina; Jordaan, Esme; Mazinu, Mikateko; Watermeyer, GillianBACKGROUND: Inter-racial differences in disease characteristics and in the management of Crohn's disease (CD) have been described in African American and Asian subjects, however for the racial groups in South Africa, no such recent literature exists. METHODS: A cross sectional study of all consecutive CD patients seen at 2 large inflammatory bowel disease (IBD) referral centers in the Western Cape, South Africa between September 2011 and January 2013 was performed. Numerous demographic and clinical variables at diagnosis and date of study enrolment were identified using an investigator administered questionnaire as well as clinical examination and patient case notes. Using predefined definitions, disease behavior was stratified as ‘complicated’ or ‘uncomplicated’. RESULTS: One hundred and ninety four CD subjects were identified; 35 (18%) were white, 152 (78%) were Cape Coloured and 7(4%) were black. On multiple logistic regression analysis Cape Coloureds were significantly more likely to develop ‘complicated’ CD (60% vs. 9%, p = 0.023) during the disease course when compared to white subjects. In addition, significantly more white subjects had successfully discontinued cigarette smoking at study enrolment (31% vs. 7% reduction, p = 0.02). No additional inter-racial differences were found. A low proportion of IBD family history was observed among the non-white subjects. CONCLUSIONS: Cape Coloured patients were significantly more likely to develop ‘complicated’ CD over time when compared to whites.
- ItemOpen AccessBaseline Predictors of Sputum Culture Conversion in Pulmonary Tuberculosis: Importance of Cavities, Smoking, Time to Detection and W-Beijing Genotype(Public Library of Science, 2012) Visser, Marianne E; Stead, Michael C; Walzl, Gerhard; Warren, Rob; Schomaker, Michael; Grewal, Harleen M S; Swart, Elizabeth C; Maartens, GaryBACKGROUND: Time to detection (TTD) on automated liquid mycobacterial cultures is an emerging biomarker of tuberculosis outcomes. The M. tuberculosis W-Beijing genotype is spreading globally, indicating a selective advantage. There is a paucity of data on the association between baseline TTD and W-Beijing genotype and tuberculosis outcomes. Aim To assess baseline predictors of failure of sputum culture conversion, within the first 2 months of antitubercular therapy, in participants with pulmonary tuberculosis. Design Between May 2005 and August 2008 we conducted a prospective cohort study of time to sputum culture conversion in ambulatory participants with first episodes of smear and culture positive pulmonary tuberculosis attending two primary care clinics in Cape Town, South Africa. Rifampicin resistance (diagnosed on phenotypic susceptibility testing) was an exclusion criterion. Sputum was collected weekly for 8 weeks for mycobacterial culture on liquid media (BACTEC MGIT 960). Due to missing data, multiple imputation was performed. Time to sputum culture conversion was analysed using a Cox-proportional hazards model. Bayesian model averaging determined the posterior effect probability for each variable. RESULTS: 113 participants were enrolled (30.1% female, 10.5% HIV-infected, 44.2% W-Beijing genotype, and 89% cavities). On Kaplan Meier analysis 50.4% of participants underwent sputum culture conversion by 8 weeks. The following baseline factors were associated with slower sputum culture conversion: TTD (adjusted hazard ratio (aHR) = 1.11, 95% CI 1.02; 1.2), lung cavities (aHR = 0.13, 95% CI 0.02; 0.95), ever smoking (aHR = 0.32, 95% CI 0.1; 1.02) and the W-Beijing genotype (aHR = 0.51, 95% CI 0.25; 1.07). On Bayesian model averaging, posterior probability effects were strong for TTD, lung cavitation and smoking and moderate for W-Beijing genotype. CONCLUSION: We found that baseline TTD, smoking, cavities and W-Beijing genotype were associated with delayed 2 month sputum culture. Larger studies are needed to confirm the relationship between the W-Beijing genotype and sputum culture conversion.
- ItemOpen AccessBlood pressure gradients and cardiovascular risk factors in urban and rural populations in Abia State South Eastern Nigeria using the WHO STEPwise approach(Public Library of Science, 2013) Okpechi, Ikechi Gareth; Chukwuonye, Innocent Ijezie; Tiffin, Nicki; Madukwe, Okechukwu Ojoemelam; Onyeonoro, Ugochukwu Uchenna; Umeizudike, Theophilus Ifeanyichukwu; Ogah, Okechukwu SamuelBACKGROUND: Developing countries of sub-Saharan Africa (SSA) face a double burden of non-communicable diseases (NCDs) and communicable diseases. As high blood pressure (BP) is a common global cardiovascular (CV) disorder associated with high morbidity and mortality, the relationship between gradients of BP and other CV risk factors was assessed in Abia State, Nigeria. METHODS: Using the WHO STEPwise approach to surveillance of chronic disease risk factors, we conducted a population-based cross-sectional survey in Abia state, Nigeria from August 2011 to March 2012. Data collected at various steps included: demographic and behavioral risk factors (Step 1); BP and anthropometric measurements (Step 2), and fasting blood cholesterol and glucose (Step 3). RESULTS: Of the 2983 subjects with complete data for analysis, 52.1% were females and 53.2% were rural dwellers. Overall, the distribution of selected CV disease risk factors was diabetes (3.6%), hypertension (31.4%), cigarette smoking (13.3%), use of smokeless tobacco (4.8%), physical inactivity (64.2%) and being overweight or obese (33.7%). Presence of hypertension, excessive intake of alcohol, smoking (cigarette and smokeless tobacco) and physical inactivity occurred more frequently in males than in females (p<0.05); while low income, lack of any formal education and use of smokeless tobacco were seen more frequently in rural dwellers than in those living in urban areas (p<0.05). The frequency of selected CV risk factors increased as BP was graded from optimal, normal to hypertension; and high BP correlated with age, gender, smokeless tobacco, overweight or obesity, annual income and level of education. CONCLUSION: Given the high prevalence of hypertension in this part of Nigeria, there is an urgent need to focus on the reduction of preventable CV risk factors we have observed to be associated with hypertension, in order to effectively reduce the burden of NCDs in Africa.
- ItemOpen AccessThe cumulative effects of polymorphisms in the DNA mismatch repair genes and tobacco smoking in oesophageal cancer risk(Public Library of Science, 2012) Vogelsang, Matjaz; Wang, Yabing; Veber, Nika; Mwapagha, Lamech M; Parker, M IqbalThe DNA mismatch repair (MMR) enzymes repair errors in DNA that occur during normal DNA metabolism or are induced by certain cancer-contributing exposures. We assessed the association between 10 single-nucleotide polymorphisms (SNPs) in 5 MMR genes and oesophageal cancer risk in South Africans. Prior to genotyping, SNPs were selected from the HapMap database, based on their significantly different genotypic distributions between European ancestry populations and four HapMap populations of African origin. In the Mixed Ancestry group, the MSH3 rs26279 G/G versus A/A or A/G genotype was positively associated with cancer (OR = 2.71; 95% CI: 1.34-5.50). Similar associations were observed for PMS1 rs5742938 (GG versus AA or AG: OR = 1.73; 95% CI: 1.07-2.79) and MLH3 rs28756991 (AA or GA versus GG: OR = 2.07; 95% IC: 1.04-4.12). In Black individuals, however, no association between MMR polymorhisms and cancer risk was observed in individual SNP analysis. The interactions between MMR genes were evaluated using the model-based multifactor-dimensionality reduction approach, which showed a significant genetic interaction between SNPs in MSH2, MSH3 and PMS1 genes in Black and Mixed Ancestry subjects, respectively. The data also implies that pathogenesis of common polymorphisms in MMR genes is influenced by exposure to tobacco smoke. In conclusion, our findings suggest that common polymorphisms in MMR genes and/or their combined effects might be involved in the aetiology of oesophageal cancer.
- ItemOpen AccessDiffering patterns of overweight and obesity among black men and women in Cape Town: the CRIBSA study(Public Library of Science, 2014) Peer, Nasheeta; Lombard, Carl; Steyn, Krisela; Gwebushe, Nomonde; Levitt, NaomiObjectives To ascertain the prevalence and determinants of overweight/obesity in the 25-74-year-old urban black population of Cape Town and examine the changes between 1990 and 2008/09. METHODS: In 2008/09, a representative cross-sectional sample, stratified for age and sex, was randomly selected from the same townships sampled in 1990. Data were collected by questionnaires, clinical measurements and biochemical analyses. Gender-specific linear regression models evaluated the associations with overweight/obesity. RESULTS: There were 1099 participants, 392 men and 707 women (response rate 86%) in 2008/09. Mean body mass index (BMI) and waist circumference (WC) were 23.7 kg/m 2 (95% confidence interval (CI): 23.1-24.2) and 84.2 cm (95% CI: 82.8-85.6) in men, and 33.0 kg/m 2 (95% CI: 32.3-33.7) and 96.8 cm (95% CI: 95.5-98.1) in women. Prevalence of BMI ≥25 kg/m 2 and raised WC were 28.9% (95% CI: 24.1-34.3) and 20.1% (95% CI: 15.9-24.9) in men, and 82.8% (95% CI: 79.3-85.9) and 86.0% (95% CI: 82.9-88.6) in women. Among 25-64-year-olds, BMI ≥25 kg/m 2 decreased between 1990 (37.3%, 95% CI: 31.7-43.1) and 2008/09 (27.7%, 95% CI: 22.7-33.4) in men but increased from 72.7% (95% CI: 67.6-77.2) to 82.6% (95% CI: 78.8-85.8) in women. In the regression models for men and women, higher BMI was directly associated with increasing age, wealth, hypertension and diabetes but inversely related to daily smoking. Also significantly associated with rising BMI were raised low-density lipoprotein cholesterol and being employed compared to unemployed in men, and having >7 years of education in women. CONCLUSIONS: Overweight/obesity, particularly in urban black women, requires urgent action because of the associations with cardiovascular disease risk factors and their serious consequences.
- ItemOpen AccessIncreased production of IL-4 and IL-12p40 from bronchoalveolar lavage cells are biomarkers of Mycobacterium tuberculosis in the sputum(Public Library of Science, 2013) Nolan, Anna; Fajardo, Elaine; Huie, Maryann L; Condos, Rany; Pooran, Anil; Dawson, Rodney; Dheda, Keertan; Bateman, Eric; Rom, William N; Weiden, Michael DBACKGROUND: Tuberculosis (TB) causes 1.45 million deaths annually world wide, the majority of which occur in the developing world. Active TB disease represents immune failure to control latent infection from airborne spread. Acid-fast bacillus (AFB) seen on sputum smear is a biomarker for contagiousness. METHODS: We enrolled 73 tuberculosis patients with extensive infiltrates into a research study using bronchoalveolar lavage (BAL) to sample lung immune cells and assay BAL cell cytokine production. All patients had sputum culture demonstrating Mycobacterium tuberculosis and 59/73 (81%) had AFB identified by microscopy of the sputum. Compared with smear negative patients, smear positive patients at presentation had a higher proportion with smoking history, a higher proportion with temperature >38.5 0 C, higher BAL cells/ml, lower percent lymphocytes in BAL, higher IL-4 and IL-12p40 in BAL cell supernatants. There was no correlation between AFB smear and other BAL or serum cytokines. Increasing IL-4 was associated with BAL PMN and negatively associated with BAL lymphocytes. Each 10-fold increase in BAL IL-4 and IL-12p40 increased the odds of AFB smear positivity by 7.4 and 2.2-fold, respectively, in a multi-variable logistic model. CONCLUSION: Increasing IL-4 and IL-12p40 production by BAL cells are biomarkers for AFB in sputum of patients who present with radiographically advanced TB. They likely reflect less effective immune control of pathways for controlling TB, leading to patients with increased infectiousness.
- ItemOpen AccessPrevalence of asthma and allergic rhinitis among adults in Yaounde, Cameroon(Public Library of Science, 2015) Pefura-Yone, Eric Walter; Kengne, André Pascal; Balkissou, Adamou Dodo; Boulleys-Nana, Julie Raïcha; Efe-de-Melingui, Nelly Rachel; Ndjeutcheu-Moualeu, Patricia Ingrid; Mbele-Onana, Charles Lebon; Kenmegne-Noumsi, Elvira Christelle; Kolontchang-Yomi, BarBACKGROUND: Population-based estimates of asthma and allergic rhinitis in sub-Saharan African adults are lacking. We assessed the prevalence and determinants of asthma and allergic rhinitis in urban adult Cameroonians. METHODS: A community-based survey was conducted from December 2013 to April 2014 among adults aged 19 years and above (N = 2,304, 57.3% women), selected through multilevel stratified random sampling across all districts of Yaounde (Capital city). Internationally validated questionnaires were used to investigate the presence of allergic diseases. Logistic regressions were employed to investigate the determinants of allergic conditions. RESULTS: Prevalence rates were 2.7% (95% CI: 2.1-3.4) for asthma-ever, 6.9% (5.9-7.9) for lifetime wheezing, 2.9% (92.2-3.6) for current wheezing and 11.4% (10.1-12.7) for self-reported lifetime allergic rhinitis; while 240 (10.4%) participants reported current symptoms of allergic rhinitis, and 125 (5.4%) had allergic rhino-conjunctivitis. The prevalence of current asthma medication use and self-reported asthma attack was 0.8 (0.4-1.2) and 1 (0.6-1.4) respectively. Multivariable adjusted determinants of current wheezing were signs of atopic eczema [2.91 (1.09-7.74)] and signs of allergic rhinitis [3.24 (1.83-5.71)]. Age group 31-40 years [0.27(0.09-0.78), p = 0.016] was an independent protective factor for wheezing. Determinants of current rhinitis symptoms were active smoking [2.20 (1.37-3.54), p<0.001], signs of atopic eczema [2.84 (1.48-5.46)] and current wheezing [3.02 (1.70-5.39)]. CONCLUSION: Prevalence rates for asthma and allergic rhinitis among adults in this population were at the lower tails of those reported in other regions of the world. Beside the classical interrelation between allergic diseases found in this study, active smoking was an independent determinant of allergic rhinitis symptoms. Nationwide surveys are needed to investigate regional variations.
- ItemOpen AccessRisk models to predict hypertension: a systematic review(Public Library of Science, 2013) Echouffo-Tcheugui, Justin B; Batty, G David; Kivimäki, Mika; Kengne, Andre PBACKGROUND: As well as being a risk factor for cardiovascular disease, hypertension is also a health condition in its own right. Risk prediction models may be of value in identifying those individuals at risk of developing hypertension who are likely to benefit most from interventions. Methods and FINDINGS: To synthesize existing evidence on the performance of these models, we searched MEDLINE and EMBASE; examined bibliographies of retrieved articles; contacted experts in the field; and searched our own files. Dual review of identified studies was conducted. Included studies had to report on the development, validation, or impact analysis of a hypertension risk prediction model. For each publication, information was extracted on study design and characteristics, predictors, model discrimination, calibration and reclassification ability, validation and impact analysis. Eleven studies reporting on 15 different hypertension prediction risk models were identified. Age, sex, body mass index, diabetes status, and blood pressure variables were the most common predictor variables included in models. Most risk models had acceptable-to-good discriminatory ability (C-statistic>0.70) in the derivation sample. Calibration was less commonly assessed, but overall acceptable. Two hypertension risk models, the Framingham and Hopkins, have been externally validated, displaying acceptable-to-good discrimination, and C-statistic ranging from 0.71 to 0.81. Lack of individual-level data precluded analyses of the risk models in subgroups. CONCLUSIONS: The discrimination ability of existing hypertension risk prediction tools is acceptable, but the impact of using these tools on prescriptions and outcomes of hypertension prevention is unclear.