In Sweden, a man’s height, weight, and smoking habits may influence his likelihood of receiving a prostate cancer diagnosis—not necessarily due to biological differences, but because of how often different groups undergo screening.
A population-based study of 171,889 Swedish men followed for 15 years found that prostate cancer risk patterns shifted significantly after PSA (prostate-specific antigen) testing became more common in the mid-1990s. The test, which detects prostate-specific proteins in the blood, is widely used for early cancer detection — but not always equally across the population.
Researchers examined men aged 50 to 64 for 15 years, analyzing how height, body mass index (BMI), and smoking status related to prostate cancer diagnosis before and after prostate-specific antigen (PSA) testing became widely used. Participants were grouped by the calendar year their data were first recorded: before 1980, between 1980 and 1994, and from 1995 to 2004.
Among the study population, 8,049 men were diagnosed with prostate cancer. Duringthe PSA testing era (1995-2004), men with obesity and current smokers were less likely to be diagnosed with prostate cancer. Obesity was linked to a 17% lower risk compared with normal weight, and current smoking was associated with a 14% lower risk compared with never smoking.
These associations were limited to non-aggressive cancers—the type typically detected through PSA screening. Researchers noted this suggests that men with obesity and smokers may be undergoing PSA testing less frequently, leading to fewer diagnoses of early-stage cancers.
In contrast, taller height was consistently associated with a slightly increased risk of both aggressive and non-aggressive prostate cancer across all time periods. This association did not change with the introduction of PSA testing and may reflect biological factors or higher screening rates among taller men.
The study used data from national Swedish health and cancer registers and applied statistical models that adjusted for factors such as age, education, marital status, and country of birth. Height and weight data were either measured or self-reported, depending on the cohort.
While PSA testing is not part of a national screening program in Sweden, many men choose to get tested. Previous studies have shown that men who are taller, of normal weight, and non-smokers are more likely to undergo PSA testing
Researchers emphasized that the lower prostate cancer risk observed among men with obesity and smokers does not suggest these factors are protective. Rather, the findings underscore how differences in screening uptake can influence cancer detection pattents.
This study adds to the understanding of how lifestyle and health behaviors influence cancer detection, especially in populations with opportunistic screening. It also highlights the need for equitable access to screening and careful interpretation of risk factors in cancer research.
Source: Scientific Reports
