Expected numbers of cases for each block group were computed by applying reference incidence rates for the same years (as estimated from the four administrative departments of the study area, plus the departments of Doubs and Hérault) to the person-years of each area stratified by gender and 5-year age classes.
For the study area, we calculated expected numbers of cancers as the number of subjects multiplied by reference incidence rate for that cancer by sex, age, time period, SES, distance to sea, and distance to river.
External reference incidence rates for leukaemia were calculated from published general population French cancer registers (Bas-Rhin, Doubs and Isère 1978 1992, Calvados 1978 1987, Haut-Rhin 1988–1992) (IARC, 1987; IARC, 1992; IARC, 1997).
We estimated reference incidence rates separately for total Finnish population and Finnish farmers, dividing the number of new cases of cancer by the population at risk in 1980, by sex, age, time period, and SES (in analyses of all people but not farmers).
The capital cities of these northernmost and southernmost states are located at 27.5º south and 42.9º south, respectively (table 1). Figure 1 shows the pattern of risk for multiple sclerosis for each two month period of birth, expressed as an incidence rate ratio for each period of birth relative to the reference incidence rate ratio (1.0) for May-June.
Frame of reference for these studies was based on expected incidence for random (i.e., stochastic) SNP accumulation.
Cancer incidence for one group compared to the reference group was calculated to obtain relative risk estimates.
The reference group for HPV incidence was negative for a certain type at both rounds; the reference group for HPV persistence was being positive for a certain type at baseline but negative for that type at follow-up.
The 2008 Korean National Cancer Registry served as the reference for calculating standardized incidence ratios (SIRs).
For each area A i, the expected number of cases E i is also computed using reference rates for the disease incidence (or mortality) and the sociodemographic strata (with respect to age, sex, and perhaps socioeconomic characteristics) where census data are available.
