Proportional mortality ratios

Overview of Basic Epidemiologic Study Designs. Epidemiology is the systematic study of the distribution and determinants of disease in human populations (19). Analytic research studies fall into several designs such as cohort studies, case-control studies, proportional mortality ratio (PMR) studies and cross sectional studies. The choice of a particular study design is determined by the... 

In proportional mortality ratio (PMR) studies, the observed proportions of deaths due to particular causes are compared to expected proportions calculated from the comparison group. There are two major limitations of this type of study. First, one must assume that the deaths studied are representative of the larger group, which may not be true. Second, proportions must add to one so a deficit in one cause of death category will necessarily produce excesses in other categories. 

E, EXPOSURE CASE-CONTROL PMR, PROPORTIONAL MORTALITY RATIO STUDY STUDY p It 0.05. CC,... 

A study on workers in a bearing manufacturing plant revealed significant excesses in proportional mortality ratios (PMR) from stomach cancer (PMR=2.0) and rectal cancer (PMR=3.1) among white male workers. Significant association was established between stomach cancer with precision grinding chemicals such as the water-based cutting oils and their aerosols [19]. 

Tables 1 and 2 summarise the current position, ranking those site operations, HSE process types and occupations that give rise to high accident rates, for major and over-3-day injury, respectively. These generic areas of risk will all require specific consideration during any project. Occupational health data provides mortality statistics for the long term health consequences of different occupations o. These statistics reinforce the HSE injury safety data, with proportional mortality ratios (PMRs) indicating that death from falls and accidental injuries are...

Proportionate Mortality Ratio (PMR)—The ratio of a cause-specific mortality proportion in an exposed group to the mortality proportion in an unexposed group mortality proportions may be adjusted for confounding variables such as age. Cause-specific mortality proportions can be calculated when the cohort (the population at risk) cannot be defined due to inadequate records, but the number of deaths and the causes of deaths are known. 

Standardized Proportionate Incidence Ratio (SPIR)—Similar to a Proportionate Mortality Ratio (PMR) in that it is a ratio of a proportion of a specific disease in an exposed group compared with the proportion in an unexposed group. 

In a proportionate mortality or proportionate incidence study, one compares the proportion of deaths or incident cases due to a condition of interest with that expected based on deaths or incident cases in an external, usually the general, population. When the proportions of causes of death are compared, the ratio is known as the proportionate mortality ratio (PMR). The comparison of proportions of incident cases is known as the proportionate incidence ratio (PIR). Proportional measures can be misleading since a decrement in the proportion of deaths or incident cases due to a particular cause will de facto lead to an increase in the proportion due to another cause. The commonly held view with regard to PMRs is that they are good approximations to SMRs from cohort studies when the cohort s all-canses combined SMR is equal to 1.0 (Checkoway et al. 1989). The odds ratio has also been used as a measure of association in PMR or PIR studies and may be a more appropriate measure of association for evalnating proportional measures (WHO 1999). 

British battery plant workers Proportional mortality odds ratio (PMOR) study N = 2,073 males frequency = matched, 1926-1985 Job-exposure matrix high, N=867 low, N= 1,206 Lung cancer PMOR = 0.93 Fanning (1988)... 

Four Pb worker cohorts studied for incidence and mortality linked to stomach cancer yielded evidence of increased mortality from stomach cancer, and this is summarized in Table 17.2. The studies consisted of two battery factory (Fanning, 1988 Wong and Harris, 2000) and two Pb smelter (Steenland et al., 1992 Wong and Harris, 2000) cohorts. The proportional mortality odds ratio (PMOR) for the 2,073 male British battery workers studied by Fanning (1988) was 1.34 (based on 31 stomach cancer deaths). Pb exposure was assessed using a job-exposure matrix, with frequency matching by 10-year worker age bands, 1926—1985. U.S. battery workers (male A = 4,518) in the Wong and Harris report presented with an SMR of 152.8 based on 45 stomach cancer deaths. 

Figure 1 The relative 6-year mortality hazard ratios are shown for reported usual sleep hr from 2-3 hr/night to 10 or more hr/night, relative to 1.0 assigned to the hazard for 7 hr/night as the reference standard. The solid line with 95% confidence interval bars shows results from a 32-covariate Cox proportional hazards survival model, as reported previously (3). The dotted lines show data from models that excluded subjects who were not initially healthy, i.e., who died within the first year or whose questionnaires reported any cancer, heart disease, stroke, chronic bronchitis, emphysema, asthma, or current illness (a yes answer to the question are you sick at the present time ). The dot-dash lines with X symbols show models controlling only for age, insomnia, and use of sleeping pills. Data were from 635,317 women and 478,619 men. The thin solid lines with diamonds show the percent of subjects with each reported sleep duration (right axis).

Dietary saturated fats are of particular scientific interest because of their association with CVD. In some countries, e.g. in Finland, there has been a decline in coronary heart disease (CHD) mortality along with the decreased intake of saturated and total fats [7]. Some epidemiological studies showed that total dietary fats intake is positively associated with metabolic syndrome [8-11]. De Oliveira et al [11] have recently reported that saturated fat intake greater than 10% of total caloric value represented a double risk for metabolie syndrome diagnosis, with odds ratio (OR) 2.0 (1.04-3.84). This association is mostly attributed to palmitie acid, due to the fact that excessive intake of PA increases the viseeral adipose tissue in greater proportion than other fat types [12]. Metabolic syndrome or cardiometabohc risk refers to a eluster of metabolic abnormalities including disturbances in... 

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