U.S. researchers who conducted the largest study yet into whether applying powder to the genitals increases a woman's risk of ovarian cancer were unable to definitively put to rest the issue that has prompted thousands of lawsuits against Johnson & Johnson and other companies.

Overall, the study did not find a significantly increased risk of ovarian cancer, but there appeared to be a heightened risk among certain women who used the products.

The data found that women with an intact reproductive tract — those who never had a hysterectomy or their tubes tied — who reported using baby powder had a 13 percent higher risk of developing ovarian cancer compared to women who never used the product. That risk rose to 19 percent among women who used baby powders at least once a week.