Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

Understanding how dogs encourage and motivate walking: cross-sectional findings from RESIDE

Background

Many people live with dogs but not all walk with them regularly. This study examines the demographic and behavioural factors that contribute towards owners reporting having a strong sense of encouragement and motivation to walk provided by their dogs, which we call ‘the Lassie effect’.

Methods

Data was collected from 629 dog owners participating in the RESIDE cross-sectional survey in Perth, Western Australia. Multivariable logistic regression analyses of factors associated with two separate outcome survey items ‘Dog encouragement to walk’ (how often dog encouraged me to go walking in last month) and ‘Dog motivation to walk’ (Having a dog makes me walk more).

Results

Owning a larger dog; having an increased level of attachment to dog; knowing dog enjoys going for a walk; believing walking keeps dog healthy; and having high social support from family to go walking, were positively associated with both outcomes ‘dog encouragement to walk’ and ‘dog motivation to walk’. Conversely, reporting the presence of children at home; that the child is the main person who walks with the dog; and perceiving dog-specific barriers to walking with dog daily; were negatively associated with both outcomes. In addition, ‘Dog motivation to walk’ only was positively associated with a belief walking reduces barking, and negatively with owning a dog that is overweight or a dog that is too old/sick. Reporting that the spouse/partner is main person who walks with the dog was also negatively associated with ‘dog motivation to walk’, as was increased perceived access to public open spaces with dog-supportive features.

Conclusions

There are both dog and owner factors that are associated with an owner’s sense of encouragement, and motivation to walk the dog, which in turn has been found to be associated with dog waking behaviour. These factors may be targeted in future interventions to increase and maintain physical activity levels of both people and pets.

The metabolic syndrome and cancer: Is the metabolic syndrome useful for predicting cancer risk above and beyond its individual components?

AIMS

The metabolic syndrome (MetS) is a risk factor for cancer. However, it is not known if the MetS confers a greater cancer risk than the sum of its individual components, which components drive the association, or if the MetS predicts future cancer risk.

MATERIALS AND METHODS

We linked 20,648 participants from the Australian and New Zealand Diabetes and Cancer Collaboration with complete data on the MetS to national cancer registries and used Cox proportional hazards models to estimate associations of the MetS, the number of positive MetS components, and each of the five MetS components separately with the risk for overall, colorectal, prostate and breast cancer. Hazard ratios (HR) and 95% confidence intervals (95%CI) are reported. We assessed predictive ability of the MetS using Harrell's c-statistic.

RESULTS

The MetS was inversely associated with prostate cancer (HR 0.85; 95% CI 0.72-0.99). We found no evidence of an association between the MetS overall, colorectal and breast cancers. For those with five positive MetS components the HR was 1.12 (1.02-1.48) and 2.07 (1.26-3.39) for overall, and colorectal cancer, respectively, compared with those with zero positive MetS components. Greater waist circumference (WC) (1.38; 1.13-1.70) and elevated blood pressure (1.29; 1.01-1.64) were associated with colorectal cancer. Elevated WC and triglycerides were (inversely) associated with prostate cancer. MetS models were only poor to moderate discriminators for all cancer outcomes.

CONCLUSIONS

We show that the MetS is (inversely) associated with prostate cancer, but is not associated with overall, colorectal or breast cancer. Although, persons with five positive components of the MetS are at a 1.2 and 2.1 increased risk for overall and colorectal cancer, respectively, and these associations appear to be driven, largely, by elevated WC and BP. We also demonstrate that the MetS is only a moderate discriminator of cancer risk.

Patterns of airway disease and the clinical diagnosis of asthma in the Busselton population

The aim of this study was to examine how objective measures related to lung function cluster in the general population and how the patterns relate to asthma and bronchitis as diagnosed by a doctor (DDA and DDB, respectively). A cross-sectional survey of an age-stratified random general population sample of 1,969 adults from the electoral register of Busselton (Australia) was performed in 2005-2007. Respiratory symptoms, DDA ever, DDB ever, recent wheezing and smoking history, together with anthropometric measurements, forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC), methacholine challenge or bronchodilator response, exhaled nitric oxide (eNO), skin-prick tests to common allergens, and blood eosinophil and neutrophil counts were studied. Cluster analysis (variables sex, age, atopy, FEV₁ % predicted, FEV₁/FVC, airway hyperresponsiveness, eNO, log eosinphil count, log neutrophil count and body mass index) was used to identify phenotypic patterns. Seven clusters (subjects with DDA and DDB, respectively) were identified: normal males (n=467; 7 and 13%), normal females (n=477; 12 and 18%), obese females (n=250; 16 and 28%), atopic younger adults (n=330; 21 and 17%), atopic adults with high eNO (n=130; 30 and 25%), atopic males with reduced FEV₁ (n=103; 33 and 32%) and atopic adults with bronchial hyperreactivity (n=212; 40 and 26%). The clinical diagnosis of asthma (ever) and bronchitis (ever) is not specific for any of the clustering patterns of airway abnormality.

Effect of length of stay in intensive care unit on hospital and long-term mortality of critically ill adult patients

BACKGROUND

Critical illness leading to prolonged length of stay (LOS) in an intensive care unit (ICU) is associated with significant mortality and resource utilization. This study assessed the independent effect of ICU LOS on in-hospital and long-term mortality after hospital discharge.

METHODS

Clinical and mortality data of 22 298 patients, aged 16 yr and older, admitted to ICU between 1987 and 2002 were included in this linked-data cohort study. Cox's regression with restricted cubic spline function was used to model the effect of LOS on in-hospital and long-term mortality after adjusting for age, gender, acute physiology score (APS), maximum number of organ failures, era of admission, elective admission, Charlson's co-morbidity index, and diagnosis. The variability each predictor explained was calculated by the percentage of the chi(2) statistic contribution to the total chi(2) statistic.

RESULTS

Most hospital deaths occurred within the first few days of ICU admission. Increasing LOS in ICU was not associated with an increased risk of in-hospital mortality after adjusting for other covariates, but was associated with an increased risk of long-term mortality after hospital discharge. The variability on the long-term mortality effect associated with ICU LOS (2.3%) appeared to reach a plateau after the first 10 days in ICU and was not as important as age (35.8%), co-morbidities (18.6%), diagnosis (10.9%), and APS (3.6%).

CONCLUSIONS

LOS in ICU was not an independent risk factor for in-hospital mortality, but it had a small effect on long-term mortality after hospital discharge after adjustment for other risk factors.

Long term survival after evidence based treatment of acute myocardial infarction and revascularisation: follow-up of population based Perth MONICA cohort, 1984-2005

OBJECTIVE

To examine trends in long term survival in patients alive 28 days after myocardial infarction and the impact of evidence based medical treatments and coronary revascularisation during or near the event.

DESIGN

Population based cohort with 12 year follow-up.

SETTING

Perth, Australia.

PARTICIPANTS

4451 consecutive patients with a definite acute myocardial infarction according to the World Health Organization MONICA (monitoring trends and determinants in cardiovascular disease) criteria admitted to hospital during 1984-7, 1988-90, and 1991-3.

MAIN OUTCOME MEASURES

All cause mortality identified from official mortality records and the hospital morbidity data, with death from cardiovascular disease as a secondary end point.

RESULTS

In the 1991-3 cohort, 28 day survivors of acute myocardial infarction had a 7.6% absolute event reduction (95% confidence interval 4% to 11%) or a 28% lower relative risk reduction (16% to 38%), unadjusted for risk of death, over 12 years after the incident admission compared with the 1984-7 cohort, similar to the survival of the 1988-90 cohort. The improved survival for the 1991-3 cohort persisted after adjustment for demographic factors, coronary risk factors, severity of disease, and event complications with an adjusted relative risk reduction of 26% (14% to 37%), but this was not apparent after further adjustment for medical treatments in hospital and coronary revascularisation procedures within 12 months of the incident myocardial infarction.

CONCLUSION

The improving trends in 12 year survival after a definite acute myocardial infarction are associated with progressive use of evidence based treatments during the initial admission to hospital and in the 12 months after the event. These changes in the management of acute myocardial infarction are probably contributing to the continuing decline in mortality from coronary heart disease in Australia.

Bayesian approach to predict hospital mortality of intensive care readmissions during the same hospitalisation

No specific prognostic model has been developed for patients readmitted to the intensive care unit (ICU) during the same hospitalisation. This study assesses the performance of the Acute Physiology and Chronic Health Evaluation (APACHE) II predicted mortality measured at the time of ICU readmission and whether incorporating information prior to the readmission will improve its performance to predict hospital mortality of patients readmitted to ICU during the same hospitalisation. A total of 602 readmissions during the same hospitalisation between 1987 and 2002 were identified. The first admission APACHE II predicted mortality was significantly associated with the hospital mortality only in the subgroup of patients readmitted within seven days of ICU discharge (odds ratio 1.16, 95% confidence interval 1.01 to 1.34; P = 0.035). In the subgroups of patients readmitted within seven days of discharge, the readmission APACHE II predicted mortality was also significantly better than the first admission APACHE II predicted mortality in discriminating between survivors and non-survivors (area under the receiver operating characteristic curve: 0.785 vs. 0.676, z statistic = 2.93; P = 0.003). Incorporating the first admission APACHE II predicted mortality to the readmission APACHE II predicted mortality, either by multilevel likelihood ratios or logistic regression, did not significantly improve its discrimination (area under the receiver operating characteristic curve: 0.792 vs. 0.785, z statistic = 0.52; P = 0.603). Our results suggested that information on prior ICU admission during the same hospitalisation is not as important as the severity of illness measured at the time of readmission in determining the mortality of intensive care readmissions during the same hospitalisation.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases

Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.

Left-handedness and risk of breast cancer

Left-handedness may be an indicator of intrauterine exposure to oestrogens, which may increase the risk of breast cancer. Women (n=1786) from a 1981 health survey in Busselton were followed up using death and cancer registries. Left-handers had higher risk of breast cancer than right-handers and the effect was greater for post-menopausal breast cancer (hazard ratio=2.59, 95% confidence interval 1.11–6.03).

Comparison of Acute Physiology and Chronic Health Evaluation (APACHE) II score with organ failure scores to predict hospital mortality

This study compared the performance of the Acute Physiology and Chronic Health Evaluation (APACHE) II score with two organ failure scores in predicting hospital mortality of critically ill patients. A total of 1311 consecutive adult patients in a tertiary 22-bed multidisciplinary intensive care unit (ICU) in Western Australia were considered. The APACHE II score had a better calibration and discrimination than the Max Sequential Organ Failure Score (Max SOFA) (area under receiver operating characteristic (ROC) curve 0.858 vs 0.829), Admission SOFA (area under ROC 0.858 vs 0.791), and the first day or cumulative 5-day Royal Perth Hospital Intensive Care Unit (RPHICU) organ failure score (area under ROC 0.858 vs 0.822 and 0.819, respectively) in predicting hospital mortality. The APACHE II score predicted hospital mortality of critically ill patients better than the SOFA and RPHICU organ failure scores in our ICU.

A valid semiquantitative food frequency questionnaire to measure fish consumption

OBJECTIVE

To validate a detailed semiquantitative food frequency questionnaire designed to measure habitual fish and seafood consumption.

DESIGN

Cross-sectional validation study using an independent biomarker of fish consumption.

SETTING

Perth metropolitan area, Western Australia.

SUBJECTS

Ninety-one healthy volunteers of both sexes aged 21-75 years.

METHODS

Participants completed the questionnaire and provided a fasting blood sample for erythrocyte membrane omega-3 fatty acid (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) analysis. The questionnaire was then validated by linear regression analysis of EPA and DHA levels on categories of fish and seafood and overall consumption, adjusted for age, sex, smoking status, body mass index (BMI) and alcohol intake.

RESULTS

Regression coefficients were statistically significant for most fish and seafood items with both EPA and DHA. The strongest association was observed between oily fish and EPA, whereas no significant association was observed between lean fish and omega-3 fatty acids. Variation in omega-3 fatty acids was best accounted for by a model containing variables representing different categories of fish and seafood consumption (R (2) 0.484), rather than a single variable representing overall fish and seafood consumption (R (2) 0.313).

CONCLUSIONS

This study confirms that the varying content of omega-3 fatty acids in foods are reflected in omega-3 biomarkers, and that the questionnaire is a valid measure of fish consumption that enables differentiation between cooking and processing methods and oily versus lean fish intake.

Data linkage enables evaluation of long-term survival after intensive care

Outcomes of intensive care are important to the patient and for assessment of benefit. Short-term outcomes after critical illness are well described, but less is known about long-term outcomes. This study describes the use of data linkage, combining intensive care unit (ICU) clinical data with administrative morbidity and mortality data, to assess long-term outcomes after treatment in ICU. The hospital-based cohort study was conducted in a 22-bed general ICU in a metropolitan teaching hospital. All patient admissions admitted to ICU from 1 January 1987 to 31 December 2002 were included. The prospective ICU clinical database with patient demographics, ICU diagnoses, severity of illness, daily assessment of organ failures and common daily treatments used was linked using probabilistic methods to the state-wide hospital morbidity and mortality databases to describe long-term survival. There were 26,019 ICU admissions (22,980 patients) with 25,972 records (99.8%) linked to a hospitalization event that included the index ICU admission. Unadjusted survival was 84.7% at 1 year decreasing progressively to 50.7% at 15 years. Age, type of admission, severity of illness (measured by Acute Physiologic and Chronic Health Evaluation (APACHE) II and the presence of organ failure), ICU length of stay, comorbidity (Chronic Health Evaluation and Charlson comorbidity index) and ICU admission diagnosis, were all associated with survival at 1, 3, 5, 10, and 15 year follow-up (P<0.001 at all time points). Linkage of clinical and administrative data provides a feasible method for ascertaining long-term survival after critical illness. Age, admission severity of illness, diagnosis and comorbidity influenced long-term unadjusted survival.

Reduced pulmonary function and its associations in type 2 diabetes: the Fremantle Diabetes Study

To determine whether diabetes is associated with reduced lung function, we studied 421 Anglo-Celt/European subjects, representing 20.5% of all patients with type 2 diabetes identified in an urban Australian catchment area of 120097 people. In addition to collection of detailed demographic and diabetes-specific data, spirometry was performed and forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), vital capacity (VC) and peak expiratory flow (PEF) measured. When expressed as a percentage of those predicted (%pred) for age, sex and height, the means of all spirometric measures were reduced by > or =9.5%. After controlling for smoking, age and gender in a linear regression model, HbA(1c) was not associated with any measure of lung function (P>0.13) but diabetes duration was significantly associated with FEV1(%pred) and PEF(%pred) (P< or =0.04) and had borderline associations with FVC(%pred) and VC(%pred) (P< or =0.064). In separate analyses controlling for smoking alone, age, body mass index (BMI), coronary heart disease (CHD) and retinopathy were independently and inversely associated with FVC(%pred), FEV1(%pred) and VC(%pred) (P<0.05). In sub-group analyses, these three spirometric measures were associated with BMI, CHD and diabetes duration in males, and age and BMI in females. Pulmonary function is reduced in type 2 diabetes. Diabetes duration seems a more important influence than glycaemic control, but obesity and vascular disease may also contribute.

Effects of lifestyle, coping and work-related stress on blood pressure in office workers

1. The relative importance of perceived stress compared with coping behaviours and 'lifestyle' characteristics known to influence blood pressure were studied in 337 male and 317 female office workers. 2. Males had significantly higher mean systolic (P < 0.01; t-test, 652 d.f.) and diastolic (P < 0.01; t-test, 652 d.f.) blood pressure and unhealthier lifestyles than females, particularly in the areas of alcohol intake (P < 0.01; t-test, 653 d.f.) and diet (P = 0.01; t-test, 663 d.f.) 3. In males drinking alcohol was correlated to job and home/work stress (P < 0.05), and eating more atherogenic foods was correlated to home/work stress (P < 0.05). 4. Coping by food and drug consumption was correlated with job and home/work stress (P < 0.05) in males; avoidance/denial coping was correlated with job stress in both males and females (P < 0.001) and to home/work stress (P < 0.001) in males only. Blood pressure was not correlated with stress in males or females. 5. In age-adjusted regression analyses body mass index (BMI) and lifestyle (physical inactivity, alcohol consumption and diet) made significant contributions to systolic (P = 0.02) and diastolic (P < 0.01) blood pressure and, in separate analyses, coping contributed significantly to diastolic blood pressure (P < 0.01) in males. Stress made no additional contribution to blood pressure in either analysis. 6. After including age, BMI, lifestyle and coping in males 'lifestyle' still contributed to systolic and diastolic blood pressure and coping made a significant additional contribution to diastolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Combination hormone therapy for metastatic breast cancer. An ECOG study of megestrol and aminoglutethimide

This study was performed to determine the toxicity and effectiveness of megestrol acetate used with aminoglutethimide-hydrocortisone in the treatment of patients with metastatic breast cancer. Forty-five patients were treated, 29 of whom were fully eligible. Twelve of the 45 who had diabetes and/or hypertension were also analyzed. All had measurable sites of disease. The median age was 63 years, and the median time from first recurrence to on-study was 19 months. Approximately half the patients already had chemotherapy, and about 90% had hormone therapy for advanced disease. The most common side effects were skin rash, weight gain, hyperglycemia, and renal and neurologic problems. No life-threatening or lethal toxicities were reported. The overall response rate (complete or partial) among the fully eligible patients was 34% (90% confidence intervals from 20% to 51%), with a 5-month median duration of response. Patients with soft tissue, visceral, and osseous disease responded. Seventy-two percent of fully eligible patients have progressed or relapsed. The median time to failure of treatment was 6 months, and the median survival time was 15 months.

Diabetes in part-aborigines of Western Australia

One thousand, two hundred and eighteen diabetic subjects living in and around country towns of Western Australia were screened for complications of diabetes. This population included 134 subjects of Aboriginal descent, who were compared with the Caucasoids taking part. In the Aboriginal group there was a greater proportion of Type 2 (non-insulin-dependent) diabetic patients, a relative female preponderance (69% compared with 51%) and a tendency to present at an earlier age of onset than their Caucasoid counterparts. Diabetic complications were at least as common in the Aboriginal group as in the Caucasoid patients. Indeed, retinopathy within 10 years of onset of diabetes was more common in the Aborigines. Peripheral neuropathy was more prevalent in Aborigines treated by diet alone or oral hypoglycaemic agents than in Caucasoids. A much greater prevalence of proteinuria was an additional feature of the Aboriginal subgroup (29% versus 4%).

Clinical macrovascular disease in Caucasoid diabetic subjects: logistic regression analysis of risk variables

A cross-sectional study of 1084 Caucasoid diabetic subjects in rural Western Australia revealed a high rate of clinical macrovascular disease (46%), including coronary heart disease (13%), stroke (8%), and peripheral vascular disease (38%). Age was the major time-related variable for total macrovascular disease and for peripheral vascular disease, with identical prevalence rates in Type 1 (insulin-dependent) and Type 2 (non-insulin-dependent) diabetes when age was taken into account. In 179 Type 1 diabetic subjects, logistic regression analysis showed no associated risk factors other than age. In 905 Type 2 diabetic subjects the independent risk factors for total macrovascular disease, identified by a forward step-wise selection procedure, were age as the major contributor, with plasma creatinine levels and plasma glucose levels (all p less than 0.001), high-density lipoprotein cholesterol levels, serum total cholesterol levels, and the (supine-erect) systolic blood pressure difference (all p less than 0.05). There were no direct associations with percentage desirable weight, cigarette smoking or male sex. Type 2 diabetic subjects demonstrated a very strong negative association between high-density lipoprotein cholesterol levels and coronary heart disease, and significant associations were found also between plasma glucose levels and coronary heart disease (p less than 0.01), and glycosylated haemoglobin levels and peripheral vascular disease (p less than 0.001).