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Biomedical subjects

Shah Ebrahim

Publications and source records attributed to Shah Ebrahim.

At least 37 records · Page 2Linked to original sources
PubMed2006

Do perceptions of neighbourhood environment influence health? Baseline findings from a British survey of aging.

OBJECTIVES: To investigate the relation between perceived neighbourhood environment, social contact and support, and self efficacy, on the health of older people. DESIGN: British cross sectional population survey of people aged 65 and over. PARTICIPANTS: 999 people aged 65 plus living at home in Britain. RESULTS: Regression modelling showed that high self efficacy had a strong independent association with better self rated health status and physical functioning. Indicators of perceived neighbourhood environment that showed strong associations with both good health and functioning were: perceptions of good quality facilities in the area (social/leisure, facilities for people aged 65+, rubbish collection, health services, transport, closeness to shops, somewhere nice to walk), and high levels of neighbourliness (knows/trusts people). Perceptions of problems in the area (noise, crime, air quality, rubbish/litter, traffic, graffiti) were also predictive of poorer health. Measures of social contact and support did not show any independent associations with health or functioning. CONCLUSIONS: The unique value of this paper is in the simultaneous analysis of associations between perceived neighbourhood, social contact and support, self efficacy, and health. The consistent strength of older people's perceptions of the quality of facilities in their neighbourhoods shows that responsive reinforcement of local infrastructures might have wider health benefits. Also of interest was the strength of self efficacy as a predictor of self rated health and physical functioning. The results have implications for both neighbourhood level interventions and self management programmes in chronic illness.

Aged↗
PubMed2006

The psychosocial versus material hypothesis to explain observed inequality in disability among older adults: data from the West of Scotland Twenty-07 Study.

OBJECTIVES: The possible mechanisms for explaining health inequality are subject to debate. This study considers the roles of psychosocial and material mechanisms in observed inequalities in disability among older people. DESIGN: Cross-sectional analysis of cohort study. PARTICIPANTS: 723 respondents aged 63 years from the West of Scotland Twenty-07 Study. MAIN OUTCOME MEASURE: The Office of Population Census and Surveys Multidimensional Disability Severity Score. Respondents were dichotomised to the highest scoring tertile, and compared with the lowest and mid-tertiles combined. EXPLANATORY MEASURES: Socioeconomic position across adulthood was measured in three ways. Respondents reported perceptions of their own financial position (perceived financial hardship) across four decades of adult life. Data on possession of several indicators of material wealth (eg, ownership of television and washing machine; material conditions) during the same periods were also ascertained. Standard occupational classification was also recorded, based on longest held occupation. The relationship between the measures of socioeconomic position and disability was examined using logistic regression, adjusting for sex, morbidity and lifestyle factors. RESULTS: Perceived financial hardship and material conditions in earlier decades of life were found to be associated with reported disability. However, in the fully adjusted model, there was stronger evidence for material conditions as a predictor of disability: across four decades they remained an independent risk factor for disability after adjustment for sex, morbidity, lifestyle factors and perceived financial hardship. Those in the most deprived material conditions group had 2 1/2 times the odds of reporting severe disability than those in the reference group. After adjustment, evidence for an association between perceived financial hardship and reported disability was not convincing. CONCLUSION: The data provide evidence to support the "material" explanation for observed inequalities in reported disability among older people.

Comorbidity↗
PubMed2006

Socioeconomic status and cardiovascular disease among men: the Korean national health service prospective cohort study.

OBJECTIVES: We examined the association between socioeconomic status (SES) and myocardial infarction and stroke subtypes, including the possible mediating influence of cardiovascular risk factors. METHODS: We evaluated data on 578756 Korean male public servants aged 30 to 58 years from August 1, 1990, to July 31, 2001. RESULTS: SES had inverse associations with mortality because of myocardial infarction and stroke subtypes, which were not changed by an adjustment for, or stratification by, cardiovascular risk factors. For nonfatal events, SES had positive, null, and inverse associations with myocardial infarction, ischemic stroke, and hemorrhagic stroke, respectively. The association between SES and nonfatal myocardial infarction depended on the presence of risk factors and was positive only among men who had cardiovascular risk factors. Case-fatality after hospital admission for cardiovascular diagnoses was significantly lower among higher SES groups, even after risk factor adjustment. CONCLUSIONS: Inverse SES associations with cardiovascular diseases were not mediated by cardiovascular risk factors among men who were undergoing economic transition. Socioeconomically patterned access to medical care may partly explain these socioeconomic gradients.

Adult↗
PubMed2005

C-reactive protein and its role in metabolic syndrome: mendelian randomisation study.

BACKGROUND: Circulating C-reactive protein (CRP) is associated with the metabolic syndrome and might be causally linked to it. Our aim was to generate estimates of the association between plasma CRP and metabolic syndrome phenotypes that were free from confounding and reverse causation, to assess the causal role of this protein. METHODS: We examined associations between serum CRP concentration and metabolic syndrome phenotypes in the British Women's Heart and Health Study. We then compared these estimates with those derived from a mendelian randomised framework with common CRP gene haplotypes to generate unconfounded and unbiased estimates of any causal associations. FINDINGS: In a sample of British women, body-mass index (BMI), systolic blood pressure, waist-to-hip ratio, serum concentrations of HDL cholesterol and triglycerides, and insulin resistance were all associated with plasma CRP concentration. CRP haplotypes were associated with plasma CRP concentration (p<0.0001). With instrumental variable analyses, there was no association between plasma CRP concentration and any of the metabolic syndrome phenotypes analysed. There was strong evidence that linear regression and mendelian randomisation based estimation gave conflicting results for the CRP-BMI association (p=0.0002), and some evidence of conflicting results for the association of CRP with the score for insulin resistance (p=0.0139), triglycerides (p=0.0313), and HDL cholesterol (p=0.0688). INTERPRETATION: Disparity between estimates of the association between plasma CRP and phenotypes comprising the metabolic syndrome derived from conventional analyses and those from a mendelian randomisation approach suggests that there is no causal association between CRP and the metabolic syndrome phenotypes.

Aged↗
PubMed2005

WHO study on Prevention of REcurrences of Myocardial Infarction and StrokE (WHO-PREMISE).

OBJECTIVE: To determine the extent of secondary prevention of coronary heart disease (CHD) and cerebrovascular disease (CVD) in low- and middle-income countries. METHODS: A descriptive cross-sectional survey of a sample of 10 000 CHD (85.2%) and CVD (14.8%) patients (6252 men; 3748 women) was conducted over 6 months in geographically defined areas. The mean age was 59.2 years (standard deviation (SD), 10.8). Consecutive patients were recruited from a stratified random sample of primary, secondary and tertiary care facilities in defined areas in 10 countries (Brazil, Egypt, India, Indonesia, Islamic Republic of Iran, Pakistan, Russian Federation, Sri Lanka, Tunisia and Turkey). The main outcome measures were levels of lifestyle and physiological risk factors, and the use of drugs for secondary prevention of CHD and CVD. FINDINGS: Approximately 82%, 89% and 77% of patients were aware of the cardiovascular benefits of quitting smoking, a heart-healthy diet and regular physical activity, respectively. About half (52.5%) engaged in less than 30 minutes of physical activity per day, 35% did not follow a heart-healthy diet and 12.5 % were current tobacco users. Blood pressure had been measured in 93.8% (range 71-100%), blood cholesterol in 85.5% (range 29-97%) and blood sugar in 75.5% (range 65-99%) in the preceding 12 months. The proportions who had received medications among CHD and CVD patients were: aspirin, 81.2%, 70.6%; beta-blockers, 48.1%, 22.8%; angiotensin-converting enzyme inhibitor, 39.8%, 37.8%; statins, 29.8%, 14.1%, respectively. About one-fifth of patients with CHD had undergone revascularization. CONCLUSION: A significant proportion of patients did not receive appropriate medications. About 47% of patients had at least two or more modifiable risk factors (smoking, physical inactivity, hypertension, diabetes or hypercholesterolaemia). There are considerable missed opportunities for prevention of recurrences in those with established CVD in low- and middle-income countries.

Cross-Sectional Studies↗
PubMed2005

Meta-analysis of MTHFR 677C->T polymorphism and coronary heart disease: does totality of evidence support causal role for homocysteine and preventive potential of folate?

OBJECTIVES: To investigate the association between the MTHFR 677C-->T polymorphism and coronary heart disease, assessing small study bias and heterogeneity between studies. DATA SOURCES: Medline and Embase citation searches between January 2001 and August 2004; no language restrictions. STUDY SELECTION: Case-control and prospective studies of association between MTHFR 677C-->T variant and myocardial infarction, coronary artery occlusion, or both; 80 studies were included. DATA EXTRACTION: Data on genotype frequency and mean homocysteine concentrations by genotype were extracted. Odds ratios were calculated for TT genotype versus CC genotype. Heterogeneity was explored, with stratification by geographical region of the study samples, and meta-regression by difference in mean serum homocysteine concentrations (CC minus TT genotypes) was carried out. RESULTS: 26,000 cases and 31,183 controls were included. An overall random effects odds ratio of 1.14 (95% confidence intervals 1.05 to 1.24) was found for TT versus CC genotype. There was strong evidence of heterogeneity (P < 0.001, I2 = 38.4%), which largely disappeared after stratification by geographical region. Odds ratios in Europe, Australia, and North America attenuated towards the null, unlike those in the Middle East and Asia. CONCLUSIONS: No strong evidence exists to support an association of the MTHFR 677 C-->T polymorphism and coronary heart disease in Europe, North America, or Australia. Geographical variability may be due to higher folate intake in North America and Europe or to publication bias. The conclusion drawn from previous meta-analyses that folic acid, through lowering homocysteine, has a role in prevention of cardiovascular disease is in some doubt.

Case-Control Studies↗
PubMed2005

Associations of socio-economic position and disability among older women in Britain and Jyväskylä, Finland.

The aim was to compare the pattern of associations in measures of socio-economic position and disability among British and Finnish older women. In Britain data from the British Women's Heart and Health Study was used. Women from 23 towns took part in a nurse-assessed medical examination and postal questionnaire (n = 4286). In Finland, data from the Evergreen study was used. Eight hundred and four women from the city of Jyväskylä were interviewed at home. Socio-economic position was measured according to social class in childhood, education, use of a car, home ownership and previous occupation. Disability measures included questions on difficulties in washing/dressing and climbing stairs. Logistic regression analyses were conducted to examine the relationship between disability and socio-economic position. In the age-adjusted analysis of both samples increasing disability in washing/dressing and climbing stairs was associated with at least one of the measures of deprivation. The relationship between socio-economic position and disability was more distinct in the British than Finnish women. Despite adjustment for a range of confounders, the relationship between socio-economic position and disability was not much attenuated, particularly in the British women. The associations in the measures of socio-economic position and disability showed a slightly different pattern between the British and Finnish women.

Age Factors↗
PubMed2005

Does elevated plasma fibrinogen increase the risk of coronary heart disease? Evidence from a meta-analysis of genetic association studies.

OBJECTIVE: The purpose of this study was to assess whether a genetic variant associated with higher fibrinogen levels is associated with increased coronary heart disease (CHD) risk, as a test of the causal influence of fibrinogen on CHD. METHODS AND RESULTS: We performed a meta-analysis of case-control and prospective studies of the G-455-->A and C-148-->T beta-fibrinogen promoter region variants, in relation to CHD risk. The 19 studies found included 12,393 cases and 21,649 controls. Fibrinogen levels were robustly related to the genetic variants (mean increase per allele, 0.117 g/L; 95% CI, 0.091-0.142 g/L). However, the genetic variants were unrelated to CHD risk (odds ratio per allele, 0.976; 95% CI, 0.916-1.040). The predicted causal odds ratio for a 1 g/L higher plasma fibrinogen level, given the genetic variant-fibrinogen and genetic variant-CHD associations, was 0.81 (95% CI, 0.46-1.40). CONCLUSIONS: Although imprecise, the predicted causal effect of fibrinogen on CHD is clearly different from the odds ratio of 1.8 (95% CI, 1.6-2.0) for an increase of 1 g/L derived from a meta-analysis of observational studies. This evidence suggests that lowering the fibrinogen level may not, in itself, reduce CHD risk.

Coronary Disease↗
PubMed2005

Plasma adiponectin levels are associated with insulin resistance, but do not predict future risk of coronary heart disease in women.

CONTEXT: Low adiponectin levels predict type 2 diabetes, and one prospective study in men reported its independent prediction of vascular events. Many observers thus already consider adiponectin to be a major part of the "common soil" underpinning diabetes and vascular disease. OBJECTIVE: The objective of this study was to assess the association between adiponectin and incident coronary heart disease (CHD) risk in the British Women's Heart and Health Study. DESIGN: This was a prospective (4 yr) case (n = 167) control (n = 334) study nested within the 4286 women in British Women's Heart and Health Study. SETTING: The study was performed in a primary care setting. PARTICIPANTS: The study consisted of women (n = 4286) randomly selected from 23 British towns between 1999 and 2001, who were 60-79 yr of age at baseline. MAIN OUTCOME MEASURES: Association of adiponectin with CHD risk factors and incident CHD events were the main outcome measures. RESULTS: Among both cases and controls, adiponectin positively correlated with age and high-density lipoprotein cholesterol and inversely correlated with waist to hip ratio, fasting insulin, fasting glucose, homeostasis model assessment of insulin resistance scores, C-reactive protein, and triglycerides. However, despite adequate power and these associations with CHD risk factors, adiponectin did not predict CHD events in unadjusted or adjusted analyses. The relative risk ratio for a doubling of adiponectin was 0.93 (95% confidence interval, 0.78, 1.11). CONCLUSIONS: It is premature to consider adiponectin as a root for vascular disease in women despite its association with insulin resistance and diabetes. Additional prospective studies are required to determine whether there is a true sex difference in the effect of adiponectin on CHD.

Adiponectin↗
PubMed2005

Sex differences in the association between birth weight and total cholesterol. A meta-analysis.

PURPOSE: Determine whether a sex difference exists in the association between birth weight and total cholesterol later in life. METHODS: Meta-analysis of within-study differences in regression coefficients of cholesterol on birth weight. RESULTS: A total of 34 regression coefficients from 30 studies were included in the analyses; these provided data on 33,650 males and 23,129 females. There was evidence that the inverse association between birth weight and total cholesterol was stronger in males compared to females. The pooled within-study difference in age-adjusted regression coefficients was -0.03 mmol/l (-0.06, -0.01), p = 0.02 and the pooled within-study difference in age and body mass index adjusted regression coefficients was -0.04 mmol/l (-0.07, -0.02), p = 0.002. There was no evidence of heterogeneity in these meta-analyses (both p values > 0.6). CONCLUSIONS: These results provide some evidence for a sex difference in the birth weight-total cholesterol association. This is consistent with studies of fetal growth which suggest that birth size reflects different biological processes for females and males. However, other very large studies are required to confirm this finding.

Adolescent↗
PubMed2005

The associations of physical activity and adiposity with alanine aminotransferase and gamma-glutamyltransferase.

The mechanisms linking obesity and inactivity to diabetes mellitus are unclear. Recent studies have shown associations of alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) with diabetes. In a random sample of 3,789 British women aged 60-79 years, the authors examined the associations of obesity and physical activity with ALT and GGT (1999-2001). Both body mass index and waist:hip ratio were independently (of each other, physical activity, alcohol consumption, smoking, and childhood and adulthood social class) positively and linearly associated with ALT and GGT. In adjusted models, a one-standard-deviation increase in body mass index was associated with a 0.46-units/liter (95% confidence interval (CI): 0.16, 0.75) increase in ALT and a 2.14-units/liter (95% CI: 0.99, 3.30) increase in GGT. Similar results for a one-standard-deviation increase in waist:hip ratio were 13.96 (95% CI: 10.44, 17.48) for ALT and 39.44 (95% CI: 25.89, 52.98) for GGT. Frequency of physical activity was inversely and linearly associated with GGT in fully adjusted models, but the inverse association with ALT was attenuated towards the null after adjustment for body mass index and waist:hip ratio. Adjustment for ALT and GGT resulted in some attenuation of the strong linear associations of body mass index and waist:hip ratio with diabetes. These findings provide some support for the suggestion that the relation between obesity and diabetes is, at least in part, mediated by liver pathology.

Adipose Tissue↗
PubMed2005

Breastfeeding and atherosclerosis: intima-media thickness and plaques at 65-year follow-up of the Boyd Orr cohort.

OBJECTIVES: The impact of breastfeeding in infancy on cardiovascular disease risk is uncertain. We related breastfeeding in infancy to atherosclerosis in adulthood. METHODS AND RESULTS: A historic cohort study based on a 65-year follow-up of the Carnegie (Boyd Orr) survey of diet and health in prewar Britain, 1937 to 1939. A total of 732 eligible cohort members living in or around Aberdeen, Bristol, Dundee, Wisbech, and London were invited for follow-up examinations in 2002, and 405 (55%) participated. In models controlling for age and sex, breastfeeding was inversely associated with common carotid intima-media thickness (IMT; difference -0.03 mm; 95% CI, -0.07 to 0.01), bifurcation IMT (difference -0.19 mm; 95% CI, -0.37 to -0.01), carotid plaque (odds ratio [OR], 0.52; 95% CI, 0.29 to 0.92), and femoral plaque (OR, 0.54; 95% CI, 0.26 to 1.12), compared with bottle-feeding. Controlling for socioeconomic variables in childhood and adulthood, smoking and alcohol made little difference to effect estimates. Controlling for factors potentially on the causal pathway (blood pressure, adiposity, cholesterol, insulin resistance, and C-reactive protein) made little difference to observed associations. CONCLUSIONS: Breastfeeding may be associated with a reduced risk of atherosclerosis in later life. Measurement error and power considerations limit the extent to which conclusions about the mechanisms underlying this relationship can be made.

Aged↗
PubMed2005

What is the best strategy for reducing deaths from heart disease?

BACKGROUND TO THE DEBATE: Coronary artery disease is a major cause of death worldwide. Two very different approaches have been proposed as a way of reducing these deaths. The "high risk" approach uses tools such as risk factor scoring and carotid ultrasound to try and identify those at highest risk, and then treats them aggressively. The "population" approach aims to shift the distribution of risk factors across a population in a beneficial direction with the goal of reducing heart disease in the whole population.

Atherosclerosis↗