HealthDay News — In recent years, a trend has emerged for higher lung cancer incidence rates among young women versus young men, and these findings are widespread across countries, according to a study published online Feb. 5 in the International Journal of Cancer.
Miranda M. Fidler-Benaoudia, Ph.D., from Alberta Health Services in Calgary, Canada, and colleagues examined lung cancer incidence rates in young women versus young men in 40 countries across five continents. Lung and bronchial cancer cases were extracted for ages 30 to 64 years from 1993 to 2012.
The researchers found that the age-specific lung cancer incidence rates generally decreased in all countries among men, while rates varied across countries among women, with the trends in most countries stable or declining, although at a slower pace. As a result, among recent birth cohorts, there was an increase in female-to-male incidence rate ratios (IRRs), with significantly greater IRRs in Canada, Denmark, Germany, New Zealand, the Netherlands, and the United States. For example, for those aged 45 to 49 years in the Netherlands, IRRs increased from 0.7 to 1.5 for those born around 1948 and 1963, respectively. In 23 additional countries, patterns were similar, although nonsignificant. The smoking prevalence of women approached but rarely exceeded that of men.
“The emerging pattern of higher lung cancer incidence among young females than young males is widespread across geographic areas and income-levels, which is not fully explained by sex-differences in smoking prevalence, underscoring the need for etiologic studies,” the authors write.