Social support and ovarian cancer incidence - A Swedish prospective population-based study

Objective. Low social support is associated with worse prognosis for epithelial ovarian cancer (EOC) patients. However, few studies have explored the relation between low social support and incidence of EOC. The aim of this prospective nested case-control study was to examine whether self-perceived low social support was associated with the incidence of EOC. Methods. The Swedish Cancer Registry was used to identify participants in the Vasterbotten Intervention Programme (VIP) comprising 58,000 women, who later developed EOC. Each case was matched to four cancer free controls. The VIP uses the Social Support questionnaire, a modified version of the validated questionnaire "The Interview Schedule for Social Interaction" (ISSI) measuring quantitative (AVSI) and qualitative (AVAT) aspects of social support. Results. The risk of EOC in relation to AVSI and AVAT was similar between the 239 cases and the 941 controls after adjustment for educational level, smoking, BMI, Cambridge Physical Activity Index and age (aOR 0.85, 95% CI 0.72-1.01 and aOR 0.54, 95% CI 0.16-1.81). Lagtime was found to have no impact. A decreased risk of serous ovarian cancer was seen in women with fewer persons available for informal socializing (aOR 0.75, 95% CI 0.59-0.95). Adjusted analyses showed non-significant odds ratios below 1.0 in the vast majority of histotypes. Conclusions. A general trend towards a decreased risk of ovarian cancer associated with low AVSI and AVAT was identified. Solely the serous subtype was significantly associated with low scores of AVSI. Prospective pathophysiological and epidemiological studies regarding social support are needed. (C) 2018 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).