A new study by Harvard researchers finds former smokers have an increased risk of developing two common types of inflammatory bowel disease, compared with people who have never smoked.
The researchers looked at data from nearly 230,000 female nurses, and found those who formerly smoked had an increased risk of Crohn’s disease and ulcerative colitis, Reuters reports.
“The increased risk of ulcerative colitis following smoking cessation persisted even two decades after cessation,” said lead researcher Dr. Leslie Higuchi. She found that after taking into account risk factors such as age, weight and use of hormone therapy, women who currently smoked were 90 percent more likely to develop Crohn’s, compared with those who never smoked. Former smokers were 35 percent more likely than those who never smoked to develop the disease. The more the women smoked, the higher their risk of developing the disease.
Former smokers were 50 percent more likely than current smokers to develop ulcerative colitis, the study found. However, current smokers had the same risk of developing the disease as those who never smoked. Other studies have shown similar findings, the article notes.
The link between smoking and these diseases is not clear, Higuchi noted. The findings are published in The American Journal of Gastroenterology.