Sitting time, physical activity and cervical intraepithelial neoplasia in Australian women: a preliminary investigation.

ISSUE ADDRESSED Physical activity affects the immune system, which in turn may modify the risk of cervical intraepithelial neoplasia (CIN). The effect of sitting on CIN is unknown. This study investigated the relationship between sitting time, physical activity and the risk of CIN. METHODS Community-dwelling adult women within metropolitan Perth, Western Australia, who had had a Papanicolaou (Pap) smear test at any of five clinics and medical centres, were approached by their general practitioners. In total, 348 women were recruited and interviewed for information on sitting time, physical activity level and lifetime physical activity exposure using the International Physical Activity Questionnaire (IPAQ)--short form. Associations of exposure variables with CIN risk were assessed by unconditional logistic regression analyses. RESULTS The prevalence of abnormal Pap smear status indicating CIN was found to be 15.8%. Women with prolonged sitting duration (≥42 h per week) had significantly increased risk of CIN (adjusted OR 3.49, 95% CI 1.12-10.88) than women who sat less than 24.5h per week. Although the effect of total physical activity level was non-significant (P=0.408), being always involved in physical activity during the entire life appeared to be inversely associated with the CIN risk (P=0.036). CONCLUSIONS Prolonged sitting time was significantly associated with increased risk of abnormal Pap smear status indicating CIN. SO WHAT?: This preliminary investigation highlights a new prospect for health-promotion intervention to reduce the risk of CIN. Health practitioners should encourage women to reduce their sitting time and maintain physically active throughout their life course.