Alexithymia Is Associated with Greater Risk of Chronic Pain and Negative Affect and with Lower Life Satisfaction in a General Population: The Hisayama Study

<div><p>Introduction</p><p>Chronic pain is a significant health problem worldwide, with a prevalence in the general population of approximately 40%. Alexithymia — the personality trait of having difficulties with emotional awareness and self-regulation — has been reported to contribute to an increased risk of several chronic diseases and health conditions, and limited research indicates a potential role for alexithymia in the development and maintenance of chronic pain. However, no study has yet examined the associations between alexithymia and chronic pain in the general population.</p><p>Methods</p><p>We administered measures assessing alexithymia, pain, disability, anxiety, depression, and life satisfaction to 927 adults in Hisayama, Japan. We classified the participants into four groups (low-normal alexithymia, middle-normal alexithymia, high-normal alexithymia, and alexithymic) based on their responses to the alexithymia measure. We calculated the risk estimates for the criterion measures by a logistic regression analysis.</p><p>Results</p><p>Controlling for demographic variables, the odds ratio (OR) for having chronic pain was significantly higher in the high-normal (OR: 1.49, 95% CI: 1.07–2.09) and alexithymic groups (OR: 2.56, 95% CI: 1.47–4.45) compared to the low-normal group. Approximately 40% of the participants belonged to these two high-risk groups. In the subanalyses of the 439 participants with chronic pain, the levels of pain intensity, disability, depression, and anxiety were significantly increased and the degree of life satisfaction was decreased with elevating alexithymia categories.</p><p>Conclusions</p><p>The findings demonstrate that, in the general population, higher levels of alexithymia are associated with a higher risk of having chronic pain. The early identification and treatment of alexithymia and negative affect may be beneficial in preventing chronic pain and reducing the clinical and economic burdens of chronic pain. Further research is needed to determine if this association is due to a causal effect of alexithymia on the prevalence and severity of chronic pain.</p></div

Odds ratios for chronic pain according to the TAS-20 subscales, adjusted for demographic factors in the general population.

<p>Odds ratios for chronic pain according to the TAS-20 subscales, adjusted for demographic factors in the general population.</p

Characteristics of the study population according to the TAS-20 score level.

<p>Values are means ± std. dev. or frequencies or median (interquartile range).</p><p>The TAS-20: the 20-item Toronto Alexithymia Scale.</p

In vitro analysis on RECQL1 expression.

<p>(A) RECQL1 expression levels in ten OC cell lines. RECQL1 expression was found to be exceptionally high in KOC-2S, KOC-3S, OVCAR-3, OVCAR-5, KOC-7C, SK-OV-3 and Tov-112D ovarian cancer cell lines as compared with the two normal cell lines (ARPE-19 and TIG-3). (B) The effect of RECQL1 silencing on the growth of OC cell line by time-course analysis. A total of ten OC cell lines were transfected with either RECQL1-siRNA (solid circle) or NS-siRNA (triangle) for a period of 120 hours as described in the Materials and Methods. Cell viability decreased with time after siRNA treatment. RECQL1-siRNA significantly inhibited the proliferation of a wide range of OC cell lines in accordance with the reduction of RECQL1 mRNA (shown as histograms). During the time-course, RECQL1 mRNA expression was reduced differentially, depending on cell line. Data represent the means ± SD, n = 3. (C) The effect of RECQL1 silencing on the cell cycle of OC cell line measured by flow cytometric analysis. Cell lines were transfected with either NS-siRNA (Upper panels) or RECQL1-siRNA (lower panels) for 72 hours. The percentage of cell populations in the subG1, G1/S and G2/M stages are shown as mean ± SD in each flow cytometric profile.</p

The relationship between the TAS-20 score levels and the pain-related outcomes of the 439 participants with chronic pain.

<p>Values are medians (interquartile range).</p><p>Pain intensity, disability and life satisfaction were evaluated by Visual Analogue Scale.</p><p>Depression and anxiety scores were evaluated by Symptom Check List-90-R.</p

Histological features and RECQL1

<div><p><b>(++) expression in ovarian cancers. </b></p> <p>(A) Serous adenocarcinoma, (B) Clear cell adenocarcinoma (C) Endometrioid adenocarcinoma, (D) Mucinous adenocarcinoma and (E) intact ovarian stroma as negative control (inset: hematoxylin and eosin staining).</p></div

Tumor cell proliferation index and survival estimate.

<p>(A) Correlation between Ki-67 labeling index and RECQL1 (++) cases. Photomicrograph illustrates high Ki-67 staining in the serous adenocarcinoma. RECQL1 (++) cases were significantly associated with high Ki-67LI (p=0.02). (B) Kaplan-Meier survival estimate between RECQL1 (++) and (+), (-) cases. By log-rank analysis, there was no significance between RECQL1 expression and overall survival (p=0.72).</p

Cut-off values of total adiponectin level for managing risk of developing MetS according to top five log likelihoods in each survival distribution.

<p>Cut-off values were confined to top five log likelihoods in each survival distribution.</p><p>* Comparison was made between subjects with total adiponectin level ≤ cut-off value and subjects with total adiponectin level > cut-off value.</p><p>Multivariate adjustment was performed for age, BMI, smoking habit, alcohol intake, and regular exercise.</p><p>MetS, metabolic syndrome; AIC, Akaike’s information criterion</p><p>Cut-off values of total adiponectin level for managing risk of developing MetS according to top five log likelihoods in each survival distribution.</p

TR and 95% CI for development of MetS according to total adiponectin level at baseline based on Weibull distribution.

<p>Multivariate adjustment was performed for age, BMI, smoking habit, alcohol intake, and regular exercise.</p><p>MetS, metabolic syndrome; TR, time ratio</p><p>TR and 95% CI for development of MetS according to total adiponectin level at baseline based on Weibull distribution.</p