Proportional mortality ratio studies

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

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. 

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]. 

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. 

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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