Depressive symptoms and life satisfaction in elderly women are associated with natural killer cell number and cytotoxicity.

Well-preserved natural killer (NK) cell cytotoxicity (NKCC) is associated with healthy aging. The objective of the survey was to investigate psychological factors related to NKCC and NK cell populations in elderly women. A cross-sectional study involving 181 participants was conducted using the Japanese version of the 28-item General Health Questionnaire (GHQ) and additional questions assessing psychological status and lifestyle. Spearman's rank test revealed a significant negative correlation between NKCC and the GHQ depression subscale (GHQ-D) scores. Significantly reduced NKCC was found in participants presenting high GHQ-D scores (12 < or = GHQ-D, n = 58) compared with those showing middle (8 < or = GHQ-D < or = 11, n = 55) or low (GHQ-D = 7, n = 68) scores. Adjusting for covariates regarding lifestyle, multiple logistic regression analysis was applied; consequently, significant associations were found between reduced NKCC and high depressive symptoms and between increased NK cell numbers and life satisfaction. These results indicated a clue to longitudinal studies in the future.