Demographic and Life Styles Determinants of Somatic Complaints’ Structures: A Cross-sectional Study on a Large Sample of Iranian Adults Using Factor Mixture Model

BACKGROUND: To identify somatic complaints dimensions, classify studied population and study the association of demographic and lifestyle factors with somatic complaints dimensions. METHODS: In a cross-sectional study conducted on 4763 Iranian adults, somatic complaints were assessed using a comprehensive 30-item questionnaire. Self-administered standard questionnaires were used to assess demographic and lifestyle factors. Factor mixture modeling (FMM) was used to identify somatic complaints dimensions and classify studied population. RESULTS: The mean age of participants was 36.58 ± 0.13 years, 55.8% were females, 81.2% were married, and 57.2% had college education. About 9.4% of individuals were obese, and 34.8% of participants had regular physical activity. Four domains of somatic complaints were extracted, including “psychological,” “gastrointestinal,” “neuro-skeletal,” and “pharyngeal-respiratory.” Females, obese and inactive participants, and those in low educations had significantly greater scores in terms of four domains than the others (P < 0.05). A two-class, four-factor structure fitted to the somatic complaints based on FMM. Two classes were labeled “high psychological complaints” (519 individuals (11%) and “low psychological complaints” (4243 individuals (89%). There were no significant differences between two classes in terms of demographic and lifestyle factors, except in educational level. CONCLUSIONS: This study suggested that somatic complaints had a dimensional-categorical structure within studied population so that it could be useful for dealing with diagnostic and therapeutic approaches. The results did not show any association between somatic complaints dimensions and demographic, lifestyle factors, except in educational level.