Biomedical subjects
Publications and source records attributed to Nicholas Day.
Repression of virulence by Staphylococcus aureus strains from different Agr groups has been demonstrated in vitro and is proposed as a means of competitive interference. Here, using the insect Manduca sexta, we show for the first time that this interference also occurs in vivo within a mixed population.
BACKGROUND: The health benefits of physical activity are well established, but the overall amount of physical activity associated with cardiovascular and other health outcomes, and whether the relationships are similar in men and women and at different ages is still debated. This may be partly related to different methods for assessing physical activity. Most studies have focused on leisure time physical activity. METHODS: We examined the prospective relationship between usual physical activity, taking into account both leisure and work activity, using a simple, pragmatic, four-point rating scale validated against heart rate monitoring, and cardiovascular disease incidence and total mortality after an average 8 years follow-up in 22,191 community living men and women aged 45-79 years with no known cardiovascular disease or cancer at baseline. RESULTS: The relative risks (95% confidence interval) for all-cause mortality (1,553 deaths) for men and women who were moderately inactive, moderately active, and active compared with those who were inactive were 0.83 (0.73-0.95), 0.68 (0.58-0.80), and 0.68 (0.57-0.81), respectively, after adjusting for age, sex, systolic blood pressure, blood cholesterol, cigarette smoking, alcohol intake, diabetes, body mass index, and social class. The relationships were also consistent for cardiovascular disease incidence (3,079 events), in subgroups stratified by age, sex, body mass index, smoking status and social class, and after excluding deaths in the first 2 years. The combined scale was more consistently associated with mortality than the individual work and leisure time components separately. CONCLUSIONS: When both work and leisure time physical activity patterns are taken into account, using a simple, pragmatic, validated questionnaire feasible for use in clinical and public health practice, even very moderate levels of usual physical activity are associated with significantly reduced risk of mortality and cardiovascular disease in men and women in the general population and potential population attributable impact of 14% for inactive compared with active levels. These findings may encourage efforts to increase physical activity levels not only in leisure time but also in usual daily working life.
AIMS: Central adiposity has been linked with adverse metabolic profile including dyslipidaemia but recent studies suggested that peripheral fat distribution play a role in regulating daily fluxes in circulating non-esterified fatty acids. We examine whether lipid levels vary between central and peripheral fat distribution in the general population. METHODS AND RESULTS: We examined the cross-sectional relation between fat distribution indices and lipid concentration in 20,021 apparently healthy men and women of the Norfolk cohort of the European Investigation into Cancer and Nutrition (EPIC-Norfolk). Waist-hip ratio was positively related to total and low density lipoprotein (LDL) cholesterol and negatively related to high density lipoprotein (HDL) cholesterol in both men and women, independently of body mass index (BMI). Although similar results were noted for waist circumference, individuals with bigger hip circumference had lower total and LDL-cholesterol and higher HDL-cholesterol when adjusting for BMI and/or waist circumference in both men and women. CONCLUSION: Regional fat distribution was related to lipid profile independently of BMI. The independent contribution of waist and hip circumference in opposite directions was intriguing. These findings may help explain the associations observed between different fat distribution phenotypes and coronary heart disease.
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A serological study was performed to determine recent human exposure to Burkholderia pseudomallei (the cause of melioidosis) in residents of southern Thailand affected by the tsunami of 26 December 2004. The findings were suggestive of increased recent exposure in both tsunami survivors and uninjured bystanders. Survivors of the Thailand tsunami may be at increased risk of melioidosis.
OBJECTIVE: The purpose of this study was to examine the relationship between breast arterial calcification (BAC), commonly found on mammography, and cardiovascular disease and its risk factors. SUBJECTS AND METHODS: The study population, nested within the European Prospective Investigation of Cancer-Norfolk (EPIC-Norfolk) cohort study, consisted of 1,590 women older than 55 years, not taking hormone replacement therapy, and with available screening mammograms. Mammograms were coded by three radiologists for presence or absence of BAC. History of coronary heart disease (CHD), stroke, and diabetes and risk factors for cardiovascular disease (including smoking status, body mass index [BMI], blood pressure, diabetes, and glycosylated hemoglobin [HbA1c]) were independently measured from health examinations in the EPIC study. RESULTS: The prevalence of BAC was 16.0%. Women with BAC were significantly older than those without it. BAC was associated with prevalent CHD, but not stroke. The odds ratio of having CHD was 2.54 (95% confidence interval, 1.03-6.30). The sensitivity and specificity were 32.4% and 85.5%, respectively. Except for smoking, which showed an inverse association, there was no consistent significant association of BAC with cardiovascular disease risk factors including BMI, diabetes, HbA1c, or lipids. CONCLUSION: BAC found on mammograms was associated with prevalent CHD after adjustment for age, but with low sensitivity. BAC may provide additional information toward identifying cardiovascular disease risk among otherwise healthy women.
The etiology of bloodstream infections in febrile patients remain poorly characterized in Nepal. A retrospective study of febrile patients presenting to Dhulikhel Hospital Kathmandu University Teaching Hospital from July 2002 to June 2004 was performed to evaluate the etiology of bloodstream infections and the drug sensitivity patterns of cultured organisms. The medical and laboratory records of all febrile patients with an axillary temperature > or = 38 degrees C who had a blood culture taken (n = 1,774) were retrieved and analyzed. Of these, 122 (6.9%) patients had positive blood cultures, of which 40.1% were age 11 to 20 years. The male to female ratio was 1.7:1. Antibiotics had been taken prior to hospital presentation by 39 (32%) patients. Salmonella enterica serovar Typhi and serovar Paratyphi A were isolated in 50 (41.0%) and 13 (10.7%) cases, respectively. All S. Typhi and S. Paratyphi isolates were susceptible to ceftriaxone, while susceptibility to ciprofloxacin and chloramphenicol was recorded in 94.8% and 94.5% of cases, respectively. Cephalexin and amoxicillin had the lowest rates of susceptibility (64.2% and 54.1%, respectively). Salmonella spp were usually sensitive to chloramphenicol. These findings provide clinicians in this region of Nepal with a better understanding of the spectrum of pathogens causing bloodstream infections and will help guide empiric antibiotic choice.
BACKGROUND: Parkinsonian symptoms have been associated with increased morbidity and mortality. Several studies have reported on the prevalence of signs and symptoms. Symptoms questionnaires can identify potential PD cases for further neurological examination to save resources. They can also provide information about how much of the population reports specific signs and symptoms. The objective of the study was to determine the self-reported prevalence of parkinsonian symptoms from a questionnaire, and to examine their association with age and self-reported Parkinson's disease in a large cohort. METHODS: A cross-sectional study was conducted within a sub-cohort of the EPIC-Norfolk (European Prospective Investigation of Cancer) cohort study. RESULTS: The prevalence of six self-reported parkinsonian symptoms are reported for 11,539 individuals who answered all symptoms questions (62% of sub-cohort): rest tremor (4%), difficulty starting to walk (4%), difficulty getting out of a chair (6%), slower walking (34%), smaller handwriting (micrographia- 9%), and less acute sense of smell (olfactory dysfunction- 9%). The presence of individual symptoms increased with age except for difficulty getting out of a chair. CONCLUSION: The results support previous findings that the presence of self-reported parkinsonian symptoms is strongly associated with age and self-reported PD diagnosis. The data also provide information regarding the prevalence of symptoms in a large, younger population of adults than previously reported in the literature.
Cerebrospinal fluid (CSF) cryptococcal colony-forming unit counts and CSF cryptococcal antigen titers serve as alternative measures of organism load in cryptococcal meningitis. For these measures, we correlated baseline values and rates of decline during the first 2 weeks of therapy in 68 human immunodeficiency virus--seropositive patients with cryptococcal meningitis. At baseline, there was a strong correlation between CSF cryptococcal colony-forming unit counts and CSF cryptococcal antigen titers. During the first 2 weeks of therapy, CSF cryptococcal colony-forming unit counts decreased by >5 logs, and CSF cryptococcal antigen titers decreased by 1.5 dilutions. In individual patients, there was no correlation between the rate of decline in CSF cryptococcal colony-forming unit counts and that in CSF cryptococcal antigen titers.
In animal models, immunity to cryptococcal infection, as in many chronic fungal and bacterial infections, is associated with a granulomatous inflammatory response, intact cell-mediated immunity, and a Th1 pattern of cytokine release. To examine the correlates of human immunity to cryptococcal infection in vivo, we analyzed immune parameters at the site of infection over time and assessed the rate of clearance of infection by serial quantitative cerebrospinal fluid (CSF) fungal cultures in 62 patients in a trial of antifungal therapy for HIV-associated cryptococcal meningitis. CSF IL-6, IFN-gamma, TNF-alpha, and IL-8 were significantly higher in survivors compared with nonsurvivors. There were negative correlations between log TNF-alpha, IFN-gamma, and IL-6 levels and baseline cryptococcal CFU. Log IFN-gamma, G-CSF, TNF-alpha, and IL-6 were correlated positively with the rate of fall in log CFU/ml CSF/day. In a linear regression model including antifungal treatment group, baseline CFU, and these cytokines, only treatment group and log IFN-gamma remained independently associated with rate of clearance of infection. The results provide direct in vivo evidence for the importance of quantitative differences in IFN-gamma secretion in human immune control of granulomatous infections, and increase the rationale for adjunctive IFN-gamma in the treatment of refractory HIV-associated cryptococcosis.
OBJECTIVE: To examine the relationship between cigarette smoking habits and fat distribution in a population-based cohort of men and women. RESEARCH METHODS AND PROCEDURES: We analyzed cross-sectional data from 21,828 men and women who were 45 to 79 years of age, residents in Norfolk, United Kingdom, and were recruited between 1993 and 1997. Cigarette smoking habits and other lifestyle factors were assessed using self-reported questionnaires. Anthropometric measures were obtained during a health examination. RESULTS: Waist-hip ratio was highest among current smokers and least among never smokers after adjusting for age, BMI, alcohol intake, total energy intake, physical activity, and education. Higher waist-hip ratio was directly associated with higher smoking pack-years in current and former smokers and inversely with duration since quitting smoking in former smokers. Adjusting for age, BMI, and other covariates, current smokers had higher waist circumference but lower hip circumference compared with former or never smokers. DISCUSSION: Cigarette smoking habits seem to influence fat distribution patterns. Although smokers have lower mean BMI compared with nonsmokers, they have a more metabolically adverse fat distribution profile, with higher central adiposity. The explanation for this association may help elucidate the mechanisms underlying the adverse health consequences of cigarette smoking and abdominal obesity.
BACKGROUND: Antioxidants, such as ascorbic acid, play a role in scavenging free radicals to protect against oxidative endothelial damage. Excess fat may promote fatty acid oxidation and increase free radical concentrations, which could result in increased antioxidant use. Whether plasma ascorbic acid concentrations are associated with fat distribution remains unclear. OBJECTIVE: Our aim was to examine the association between abdominal obesity, as measured by the waist-to-hip ratio, and plasma ascorbic acid concentrations in the general population. DESIGN: We examined the cross-sectional relation between anthropometric measurements of fat distribution and plasma ascorbic acid concentrations in 19 068 men and women aged 45-79 y without known chronic illness. Dietary ascorbic acid intake was estimated for a subgroup of 8178 men and women who kept 7-d food diaries coded for nutrient intake. RESULTS: The waist-to-hip ratio was inversely related to plasma ascorbic acid concentrations in both men and women. This association was independent of body mass index, age, vitamin supplement use, cigarette smoking, and socioeconomic group. Waist and hip circumferences showed separate and opposite associations with plasma ascorbic acid concentrations, independent of body mass index and other covariates. Dietary ascorbic acid intake only partly explained the observed associations. CONCLUSIONS: Plasma ascorbic acid was associated with fat distribution independent of body mass index. Differences in dietary intake and lifestyle habits, underlying systemic oxidative stress, or both may explain the inverse relation between fat distribution and plasma ascorbic acid concentrations. Additional studies are needed to determine the underlying explanation of these observations.
The mapW gene of Staphylococcus aureus strain N315 contains a poly(A) tract which truncates translation of the protein. This study demonstrates that mapW is an allelic variant of the map/eap genes found in other strains and that the variation in the length of this poly(A) tract suggests that it is a contingency locus.
BACKGROUND: Increasing evidence suggests a continuous relationship between blood glucose concentrations and cardiovascular risk, even below diagnostic threshold levels for diabetes. OBJECTIVE: To examine the relationship between hemoglobin A1c, cardiovascular disease, and total mortality. DESIGN: Prospective population study. SETTING: Norfolk, United Kingdom. PARTICIPANTS: 4662 men and 5570 women who were 45 to 79 years of age and were residents of Norfolk. MEASUREMENTS: Hemoglobin A1c and cardiovascular disease risk factors were assessed from 1995 to 1997, and cardiovascular disease events and mortality were assessed during the follow-up period to 2003. RESULTS: In men and women, the relationship between hemoglobin A1c and cardiovascular disease (806 events) and between hemoglobin A1c and all-cause mortality (521 deaths) was continuous and significant throughout the whole distribution. The relationship was apparent in persons without known diabetes. Persons with hemoglobin A1c concentrations less than 5% had the lowest rates of cardiovascular disease and mortality. An increase in hemoglobin A1c of 1 percentage point was associated with a relative risk for death from any cause of 1.24 (95% CI, 1.14 to 1.34; P < 0.001) in men and with a relative risk of 1.28 (CI, 1.06 to 1.32; P < 0.001) in women. These relative risks were independent of age, body mass index, waist-to-hip ratio, systolic blood pressure, serum cholesterol concentration, cigarette smoking, and history of cardiovascular disease. When persons with known diabetes, hemoglobin A(1c) concentrations of 7% or greater, or a history of cardiovascular disease were excluded, the result was similar (adjusted relative risk, 1.26 [CI, 1.04 to 1.52]; P = 0.02). Fifteen percent (68 of 521) of the deaths in the sample occurred in persons with diabetes (4% of the sample), but 72% (375 of 521) occurred in persons with HbA1c concentrations between 5% and 6.9%. LIMITATIONS: Whether HbA1c concentrations and cardiovascular disease are causally related cannot be concluded from an observational study; intervention studies are needed to determine whether decreasing HbA1c concentrations would reduce cardiovascular disease. CONCLUSIONS: The risk for cardiovascular disease and total mortality associated with hemoglobin A1c concentrations increased continuously through the sample distribution. Most of the events in the sample occurred in persons with moderately elevated HbA1c concentrations. These findings support the need for randomized trials of interventions to reduce hemoglobin A1c concentrations in persons without diabetes.
BACKGROUND: A quarter of fractures needing admission happen in men, but few data are available that show the value of bone measures for prediction of fracture risk in men. We aimed to assess quantitative ultrasound of the calcaneum and fracture incidence in a prospective observational population study. METHODS: Calcaneum broadband ultrasound attenuation (BUA) was measured in men and women in the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk) between 1997 and 2000. Incident fractures were ascertained by hospital record linkage. FINDINGS: In 14824 men and women aged 42-82 years, during mean follow-up of 1.9 years (SD 0.7), there were 121 incident fractures that needed admission, including 31 hip fractures. Men and women in the lowest 10% of the calcaneum BUA distribution had a relative risk of fracture of 4.44 (95% CI 2.24-8.89, p<0.0001) compared with those in the upper 30% of the distribution. A fall of about 1 SD in BUA (20 db/MHz) was associated with a relative risk of fracture of 1.95 (95% CI 1.50-2.52, p<0.0001), independent of age, sex, weight, height, cigarette smoking habit, and past history of fracture. BUA predicted fractures with consistent magnitude in subgroups stratified by sex, age 65 years or older and younger than 65 years, smoking habit, past history of fracture, and hip and non-hip fractures separately. The sex difference in fracture risk was largely accounted for by differences in BUA. INTERPRETATION: Quantitative calcaneum ultrasound predicts total and hip fracture risk in men and women in a continuous relation. The challenge now is to identify interventions to improve bone health in the whole population.
We examined the association between self-reported consumption of fruits and vegetables and prostate cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). Data on food consumption and complete follow-up for cancer incidence were available for 130544 men in 7 countries recruited into EPIC between 1993 and 1999. After an average of 4.8 years of follow-up, there were 1104 incident cases of prostate cancer. The associations of consumption of total fruits, total vegetables, cruciferous vegetables and combined total fruits and vegetables with prostate cancer risk were examined using Cox regression, stratified for recruitment center and adjusted for height, weight and energy intake. There was a wide range in consumption of fruits and vegetables: mean intakes (g/day) in the bottom and top fifths of the distribution, as estimated from 24-hr recalls in a subsample of participants, were 53.2 and 410.7 for fruits, 97.1 and 242.1 for vegetables and 169.0 and 633.7 for fruits and vegetables combined. No significant associations between fruit and vegetable consumption and prostate cancer risk were observed. Relative risks (95% confidence intervals) in the top fifth of the distribution of consumption, compared to the bottom fifth, were 1.06 (0.84-1.34) for total fruits, 1.00 (0.81-1.22) for total vegetables and 1.00 (0.79-1.26) for total fruits and vegetables combined; intake of cruciferous vegetables was not associated with risk. These results suggest that total consumption of fruits and vegetables is not associated with the risk for prostate cancer.
BACKGROUND: Abundant evidence indicates that a high sodium intake is causally related to high blood pressure, but debate over recommendations to reduce dietary sodium in the general population continues. A key issue is whether differences in usual sodium intake within the range feasible in free-living populations have clinical or public health relevance. OBJECTIVE: We examined the relation between blood pressure and urinary sodium as a marker of dietary intake. DESIGN: This was a study of 23104 community-living adults aged 45-79 y. RESULTS: Mean systolic and diastolic blood pressure increased as the ratio of urinary sodium to creatinine increased (as estimated from a casual urine sample), with differences of 7.2 mm Hg for systolic blood pressure and 3.0 mm Hg for diastolic blood pressure (P < 0.0001) between the top and bottom quintiles. This trend was independent of age, body mass index, urinary potassium:creatinine, and smoking and was consistent by sex and history of hypertension. The prevalence of those with systolic blood pressure >/= 160 mm Hg halved from 12% in the top quintile to 6% in the bottom quintile; the odds ratio for having systolic blood pressure >/= 160 mm Hg was 2.48 (95% CI: 1.90, 3.22) for men and 2.67 (95% CI: 2.08, 3.43) for women in the top compared with the bottom quintile of urinary sodium. Estimated mean sodium intakes in the lowest and highest quintiles were approximately 80 and 220 mmol/d, respectively. CONCLUSIONS: Within the usual range found in a free-living population, differences in urinary sodium, an indicator of dietary sodium intake, are associated with blood pressure differences of clinical and public health relevance. Our findings reinforce recommendations to lower average sodium intakes in the general population.
OBJECTIVE: To determine the relation between fat distribution and blood pressure, independent of body mass index. DESIGN: Cross-sectional, population-based study. PARTICIPANTS AND METHODS: Participants, 9936 men and 12,154 women aged 45-79 years, were recruited from general practices in Norfolk, United Kingdom for the European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk) study. Participants filled in a health and lifestyle questionnaire and their blood pressure and anthropometry were measured at a clinic. We mainly used waist-hip ratio (WHR) to assess body fat distribution. RESULTS: Systolic blood pressure (SBP) and diastolic blood pressure (DBP) increased linearly across the whole range of waist-hip ratio in both men and women. The relation was independent of age, body mass index (BMI) and other covariates. Separately, waist and hip circumferences were positively related to SBP and DBP. When adjusted for BMI, waist circumference was positively related to SBP (in women) and DBP (in both men and women), whereas hip circumference was inversely related to SBP (but not DBP) in both men and women. Stratifying by tertiles of waist and hip circumference, age- and BMI-adjusted SBP and DBP were highest among those with high waist and small hip circumference measures. CONCLUSION: Waist-hip ratio was independently related to blood pressure. Waist-hip ratio could reflect the separate and opposite relations of waist and hip circumferences on blood pressure. Characterizing patterns of fat distribution may have implications in the assessment and control of obesity-related blood pressure elevation.