Association between use of straighteners and other hair products with risk of uterine cancer

Hair products may contain chemicals with endocrine-disrupting and carcinogenic properties. Previous studies have found hair product use to be associated with higher risk of hormone-sensitive cancers including breast an ovarian cancer. Analysis among participants of the Sister Study found that ever versus never use of straightening products in the 12 months previous to inclusion was associated with higher incident uterine cancer rates (HR 1.80; 95% CI 1.12-2.88). The association was stronger when comparing frequent use (more than 4 times in the past 12 months) versus never use (HR 2.55; 95% CI 1.46-4.45). Use of other hair products was not associated with incident uterine cancer.