The research, based on some 150,000 people in the U.S, continental Europe, and the UK, suggests this could be due to improvements in education, a decline in smoking, and a reduction in air pollution.

Credits: envato elements;

In the U.S., 25.1 percent of people born between 1890 and 1913 developed the condition, compared with 15.5 percent of those born between 1939 and 1943, backing similar trends observed in continental Europe and England.