We investigated if cancer onset in offspring is related to having short-lived parents for different cancer types and to see if there was a difference in smoking- and non-smoking related cancers.
Our study included 524,391 individuals born in Norway 1940-1950. All children were followed up for cancer from the age of 20 until they were between 59 and 69 years. Parental longevity was examined by grouping parental age of death into parents dying before 75 years of age and parents dying at 75 years of age or older.
An increased risk of 1.14 (95%CI=1.10-1.19) among male offspring and 1.08 (95%CI=1.04-1.12) among female offspring was observed for total cancer when both parents died before the age of 75 compared to offspring with two long-lived parents. The highest increase was found for cancer in the lungs and trachea for both male (HR=1.67, 95%CI=1.50-1.86) and female offspring (HR=1.53, 95%CI=1.33-1.76). For other smoking-related cancers, the risk was lower. No increased risk was observed for non-smoking-related cancers.
Offspring of long-lived parents have lower risk of developing cancer compared with offspring of short-lived parents. Intergenerational transmission of risk factors from parents to offspring may play an important role, especially for tobacco-related cancers. However, genetic factors cannot be ruled out, since consistent evidence has implicated genetic factors in smoking behaviour.