Evaluation of dietary antioxidant capacity, chronotype, sleep disorders, and oxidative stress parameters in patients with fibromyalgia syndrome

This study aimed to evaluate dietary antioxidant capacity, chronotype, sleep disturbances, and oxidative stress parameters in individuals with and without fibromyalgia syndrome (FMS). The study included a total of 78 volunteers, comprising 39 individuals diagnosed with FMS (FMS group) and 39 healthy individuals without an FMS diagnosis (control group). Data were collected through face-to-face interviews using a questionnaire. The participants' daily dietary energy and nutrient intakes were assessed using the 24-hour retrospective food consumption recording method. Anthropometric measurements were conducted by the researcher. Dietary antioxidant capacity (DTAC) was calculated based on antioxidant food consumption frequency data. Routine biochemical findings and serum antioxidant/oxidant status were evaluated using total antioxidant capacity (TAC), total oxidant capacity (TOC), dynamic thiol-disulfide balance (native thiol, total thiol, native/total thiol, disulfide, disulfide/native thiol, disulfide/total thiol), and ischemia-modified albumin (IMA) parameters. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), chronotypes were determined using the Morningness-Eveningness Questionnaire (MEQ), and depression levels were evaluated using the Beck Depression Inventory (BDI). The Fibromyalgia Impact Questionnaire (FIQ) and Visual Analog Scale (VAS) were used to assess the disease status of the FMS group. Daily dietary intakes of insoluble fiber, vitamin E, vitamin K, and folate were significantly higher in women from the FMS group (11.7±4.56 g, 18.2±9.12 mg, 109.5±119.31 mcg, and 290.8±100.33 mcg, respectively) compared to the control group (9.5±3.71 g, 12.7±6.10 mg, 80.8±80.43 mcg, and 250.6±132.05 mcg, respectively), while vitamin A intake was significantly lower (1015.7±558.53 mcg vs. 1218.1±100.33 mcg, p<0.05). The mean DTAC values (ORAC and FRAP) of women in the FMS group were significantly higher than those in the control group (7.6±2.48 mmol and 4.5±1.72 mmol vs. 7.4±2.45 mmol and 4.2±1.44 mmol, respectively, p<0.05). While there was no significant difference in TAC between the groups, the mean TOC value of the FMS group (5.7±0.27 µmol H2O2 Eq/L) was significantly lower than that of the control group (5.8±0.28 µmol H2O2 Eq/L, p<0.05). No significant differences were found in thiol-disulfide balance and IMA values between the FMS and control groups (p>0.05). Women in the FMS group had significantly higher PSQI and BDI scores compared to the control group (4.8±3.45 and 13.2±8.29 vs. 2.6±3.39 and 6.5±6.96, respectively, p<0.05). There was no significant difference in MEQ scores between the FMS and control groups (p>0.05). In the FMS group, native thiol and total thiol values were negatively correlated with FIQ scores (r=-0.353 and r=-0.345, respectively, p<0.05) and VAS movement scores (r=-0.494 and r=-0.489, respectively, p<0.05). Disulfide values were negatively correlated with BDI scores (r=-0.336, p<0.05) and MEQ scores (r=-0.336, p<0.05). A positive correlation was observed between ORAC and FIQ scores (r=0.471, p<0.05) as well as BDI scores (r=0.428, p<0.05). A negative correlation was found between MEQ scores and TOC values (r=-0.317, p<0.05). Logistic regression analysis showed that PSQI scores (OR=1.232; 95% CI: 1.056-1.436), BDI scores (OR=1.123; 95% CI: 1.048-1.204), and BMI (OR=1.124; 95% CI: 1.007-1.255) were significantly associated with the likelihood of having FMS (p<0.05). Daily dietary intake of omega-3 (OR=0.211; 95% CI: 0.045-0.981), omega-6 to omega-3 ratio (OR=0.765; 95% CI: 0.602-0.971), selenium (OR=1.052; 95% CI: 1.001-1.107), zinc (OR=1.250; 95% CI: 1.053-1.483), and vitamin E (OR=1.232; 95% CI: 1.066-1.424) were also associated with FMS status (p<0.05). In conclusion, this study showed that dietary antioxidant capacity was higher in individuals with FMS, while sleep quality and depression levels were worse compared to the control group. Thiol-disulfide balance and oxidative stress parameters were associated with the effects of FMS. These findings suggest that multidisciplinary approaches targeting medical nutrition therapy, oxidative stress reduction, and the improvement of sleep quality and depression levels could play a critical role in alleviating FMS symptoms.