Observed and Expected Mortality in Cohort Studies.
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SUBMITTER: Richardson DB
PROVIDER: S-EPMC5391699 | biostudies-literature | 2017 Mar
REPOSITORIES: biostudies-literature
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Observed and Expected Mortality in Cohort Studies.
Richardson David B DB Keil Alexander P AP Cole Stephen R SR MacLehose Richard F RF
American journal of epidemiology 20170301 6
Epidemiologists often compare the observed number of deaths in a cohort with the expected number of deaths, obtained by multiplying person-time accrued in the cohort by mortality rates for a reference population (ideally, a reference that represents the mortality rate in the cohort in the absence of exposure). However, if exposure is hazardous (or salutary), this calculation will not consistently estimate the number of deaths expected in the absence of exposure because exposure will have affecte ...[more]
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Project description:Red meat consumption has been associated with an increased risk of chronic diseases. However, its relationship with mortality remains uncertain.We prospectively observed 37 698 men from the Health Professionals Follow-up Study (1986-2008) and 83 644 women from the Nurses' Health Study (1980-2008) who were free of cardiovascular disease (CVD) and cancer at baseline. Diet was assessed by validated food frequency questionnaires and updated every 4 years.We documented 23 926 deaths (including 5910 CVD and 9464 cancer deaths) during 2.96 million person-years of follow-up. After multivariate adjustment for major lifestyle and dietary risk factors, the pooled hazard ratio (HR) (95% CI) of total mortality for a 1-serving-per-day increase was 1.13 (1.07-1.20) for unprocessed red meat and 1.20 (1.15-1.24) for processed red meat. The corresponding HRs (95% CIs) were 1.18 (1.13-1.23) and 1.21 (1.13-1.31) for CVD mortality and 1.10 (1.06-1.14) and 1.16 (1.09-1.23) for cancer mortality. We estimated that substitutions of 1 serving per day of other foods (including fish, poultry, nuts, legumes, low-fat dairy, and whole grains) for 1 serving per day of red meat were associated with a 7% to 19% lower mortality risk. We also estimated that 9.3% of deaths in men and 7.6% in women in these cohorts could be prevented at the end of follow-up if all the individuals consumed fewer than 0.5 servings per day (approximately 42 g/d) of red meat.Red meat consumption is associated with an increased risk of total, CVD, and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.
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Project description:BACKGROUND:Lifespan and the proportion of older people in the population are increasing, with far reaching consequences for the social, political and economic landscape. Unless accompanied by an increase in health span, increases in age-related diseases will increase the burden on health care resources. Intervention studies to enhance healthy ageing need appropriate outcome measures, such as blood-borne biomarkers, which are easily obtainable, cost-effective, and widely accepted. To date there have been no systematic reviews of blood-borne biomarkers of mortality. AIM:To conduct a systematic review to identify available blood-borne biomarkers of mortality that can be used to predict healthy ageing post-retirement. METHODS:Four databases (Medline, Embase, Scopus, Web of Science) were searched. We included prospective cohort studies with a minimum of two years follow up and data available for participants with a mean age of 50 to 75 years at baseline. RESULTS:From a total of 11,555 studies identified in initial searches, 23 fulfilled the inclusion criteria. Fifty-one blood borne biomarkers potentially predictive of mortality risk were identified. In total, 20 biomarkers were associated with mortality risk. Meta-analyses of mortality risk showed significant associations with C-reactive protein (Hazard ratios for all-cause mortality 1.42, p<0.001; Cancer-mortality 1.62, p<0.009; CVD-mortality 1.31, p = 0.033), N Terminal-pro brain natriuretic peptide (Hazard ratios for all-cause mortality 1.43, p<0.001; CHD-mortality 1.58, p<0.001; CVD-mortality 1.67, p<0.001) and white blood cell count (Hazard ratios for all-cause mortality 1.36, p = 0.001). There was also evidence that brain natriuretic peptide, cholesterol fractions, erythrocyte sedimentation rate, fibrinogen, granulocytes, homocysteine, intercellular adhesion molecule-1, neutrophils, osteoprotegerin, procollagen type III aminoterminal peptide, serum uric acid, soluble urokinase plasminogen activator receptor, tissue inhibitor of metalloproteinases 1 and tumour necrosis factor receptor II may predict mortality risk. There was equivocal evidence for the utility of 14 biomarkers and no association with mortality risk for CD40 ligand, cortisol, dehydroepiandrosterone, ferritin, haemoglobin, interleukin-12, monocyte chemoattractant protein 1, matrix metalloproteinase 9, myelopereoxidase, P-selectin, receptor activator of nuclear factor KappaB ligand, sex hormone binding globulin, testosterone, transferrin, and thyroid stimulating hormone and thyroxine. CONCLUSIONS:Twenty biomarkers should be prioritised as potential predictors of mortality in future studies. More studies using standardised protocols and reporting methods, and which focus on mortality rather than risk of disease or health status as an outcome, are needed.
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Project description:ObjectivesTo evaluate the association between restless legs syndrome (RLS) and all-cause mortality.DesignFour prospective cohort studies.SettingThe Dortmund Health Study (DHS) and the Study of Health in Pomerania (SHIP) from Germany. The Women's Health Study (WHS) and the Physicians' Health Study (PHS) from the USA.ParticipantsIn DHS: a random sample (n=1 299) from the population of Dortmund; in SHIP: a sample (n=4 291) from residents living in West Pomerania were drawn by multistage random sampling design; in WHS: female healthcare professionals (n=31 370); in PHS: male physicians (n=22 926)Main outcome measuresAll-cause mortality.ResultsThe prevalence of RLS ranged between 7.4% and 11.9% at baseline. During follow-up (ranging between 6 and 11 years) RLS was not associated with increased risk of all-cause mortality in any of the four cohorts. The multivariable-adjusted HRs (95% CI) for all-cause mortality ranged from 0.21 (0.03 to 1.53) to 1.07 (0.93 to 1.23) across the four studies. The HRs for all-cause mortality did not differ according to gender.ConclusionsIn these four independently conducted large prospective cohort studies from Germany and the USA, RLS did not increase the risk of all-cause mortality. These findings do not support the hypothesis that RLS is a risk factor for mortality of any cause.
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