Arecent study followed 900,000 us adults from 1982 to 1998. at baseline, all participants were screened and determined to be cancer free and their body mass index (bmi) was calculated. body mass index is a measure of obesity that is calculated using a person's height and weight. subjects were separated into the following groups according to their bmi: (a) normal weight, (b) slightly overweight, (c) moderately overweight and (d) greatly overweight. 57,145 deaths from cancer occurred in the population during the follow-up period. the following results were seen for men and women when the heaviest members of the cohort were compared to those with normal weight:

men: risk ratio of cancer death= 1.5 95% confidence interval= 1.1-2.1 women: risk ratio of cancer death= 1.6 95% confidence interval= 1.4-1.9

are the results bolded above confounded by gender? why?