University Gothenburg Logo Urinary incontinence occurring before middle age may be particularly common in women. It is believed that symptoms such as incontinence, overactive bladder and other lower urinary tract are triggered by factors like old age, excess weight, pregnancy, childbirth, stroke as well as other neurological disorders. A study of twins at the Sahlgrenska Academy and Karolinska Institutet now claims that genetic factors can explain half of people’s susceptibility to urinary incontinence.

As a part of the study, investigators examined over 25,000 Swedish twins aged 20 to 46. Data on urinary incontinence, overactive bladder and other lower urinary tract symptoms was assayed through a statistical method that measures how much of the difference between people is due to genetic variation. The prevalence of these symptoms in identical twins with genetic variation was compared with non-identical twins, who share half of their genetic material. As a result, the relative significance of genetic and environmental factors was seemingly highlighted.

“With urinary incontinence, we saw that just over half of the variation (51 percent) can be explained by genetic factors. This doesn’t mean that half of all people with urinary incontinence inherit it from their parents, but that around 50 percent of people’s susceptibility to urinary incontinence can be explained by their genes,” shared gynecologist Anna Lena Wennberg, one of the researchers behind the study.

It then appeared that genes are extremely important for nocturia that is the need to get up in the night for urination. Around 34 percent subjects apparently had this genetic explanation for nocturia. There may a number of genes that combine with various environmental factors or cause disorders which, in turn, raise the risk of urinary incontinence.

The study was published online in the journal European Urology.