In the comparison between CMM survivors and the general population, interactions were observed for educational attainment, attained age and calendar period (pinteraction < 0.01).
For SCC survivors in comparison to the general population, interactions were found for parental status, educational attainment, attained age and calendar period (pinteraction < 0.01).
Compared to other parous women, women with pre-eclampsia and/or hypertension diagnosed in their first pregnancy had 19% lower risk (95% confidence interval, 9 to 29%) for breast cancer, after adjustment for attained age, calendar period of diagnosis, age at first birth, and parity.
Compared with people in the oldest category (≥50 years), rate ratios were significantly lower for patients aged 0-9 (0.30, 0.17 to 0.55) or 10-19 (0.27, 0.27 to 0.64) at appendicectomy (fig 1), after adjustment for potential confounding by country, sex, attained age, calendar period, and time since the operation.
For more complex comparisons of rates of ulcerative colitis in the appendicectomy cohort we performed multiple Poisson regressions with offset variables equal to the log of the expected number of cases in strata of the examined explanatory variable and the potential confounding variables: country, sex, attained age, calendar period, time since appendicectomy, and age at appendicectomy.
Specifically, in this cohort we modelled the observed numbers of stratum specific cases as a log linear function of attained age, calendar period, and appendicectomy status, using the log of the stratum specific person years at risk in the predisposed cohort as offset.
These women had a 19% lower risk of subsequent breast cancer than the remaining women (rate ratio 0.81, 95% confidence interval 0.71 to 0.91), after adjustment for attained age, calendar period of diagnosis, age at first birth, and parity (Table 1-wrap>).
The absolute number of prostate cancers occurring reaches a maximum in the category 75 80 years of age, due to the age distribution in the cohort, and increases steadily from 1970 2003 and the cumulative number of prostate cancers increases as a function of age attained and calendar year.
31 None of the radiation covariables (ie, γ prostate dose but also including long-lived radionuclides and radon), when tested by inclusion singularly as linear risks in refined internal Poisson regression models, resulted in a deviance drop of more than three with respect to the background model which was stratified on age attained and calendar year.
We adjusted all RRs for attained age, calendar time, PLCO screening center, age at menarche, age at natural menopause, age at first birth and parity, first-degree family history of breast cancer, benign breast disease, current height, and menopausal hormone therapy use.
