title: Plasma linoleic acid partially mediates the association of bipolar disorder on self-reported mental health scales.
abstract: We have shown that bipolar individuals have reduced quality diets, including lower intake of polyunsaturated fatty acids (PUFA). We have also reported reduced plasma levels of the n-6 PUFA, linoleic acid (LA), and the n-3 PUFA, eicosapentaenoic acid (EPA) in bipolar subjects. In the current analysis we hypothesized that LA and EPA plasma levels would mediate lower self-reported mental health and life functioning scores in bipolar subjects. In a cross-sectional study, we collected a 7-day diet record in bipolar (n = 56) and control subjects (n = 46) followed by a fasted blood draw. We used structured equation modeling path analysis to test for mediating effects of dietary intake and plasma levels of LA and EPA on self-reported mental health questionnaire scores, including the Life Functioning Questionnaire (LFQ), the Patient Health Questionnaire (PHQ9), and the Short Form Health Survey (SF12), extracting the mental health component summary score (SF12-MH). We adjusted for age, gender, psychiatric medication use, body mass index (BMI), and total caloric intake as covariates with bipolar disorder as the primary predictor. We found a significant path association from bipolar disorder to lower plasma LA levels (p = 0.03) and significant paths from plasma LA to PHQ9 (p = 0.05), LFQ (p = 0.01) and SF12-MH (p = 0.05) scores, such that lower plasma LA predicted worse outcomes. We found no significant paths from plasma EPA levels to any of the outcome measures. These findings suggest that plasma LA levels partially mediate the effect of bipolar disorder on self-reported measures of mental health and life functioning.
authors.affiliation: Department of Psychiatry, University of Michigan Medical School, USA. Electronic address: evanssi@umich.edu.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Evans
authors.affiliation: Department of Psychiatry, University of Michigan Medical School, USA.
authors.forename: Shervin
authors.initials: S
authors.lastname: Assari
authors.affiliation: Department of Psychiatry, University of Michigan Medical School, USA.
authors.forename: Gloria J
authors.initials: GJ
authors.lastname: Harrington
authors.affiliation: Department of Nutrition, University of Michigan School of Public Health, USA.
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, University of Michigan Medical School, USA.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Burant
authors.affiliation: Department of Psychiatry, University of Michigan Medical School, USA.
authors.forename: Melvin G
authors.initials: MG
authors.lastname: McInnis
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000097:blood*; D003430:Cross-Sectional Studies; D015118:Eicosapentaenoic Acid / Q000097:blood; D005260:Female; D006801:Humans; D019787:Linoleic Acid / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D057566:Self Report; D011795:Surveys and Questionnaires
chemical_list: D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid
keywords: Bipolar disorder; EPA; Eicosapentaenoic acid; LA; LFQ; Life functioning questionnaire; Linoleic acid; PHQ9; Path analysis; Patient health questionnaire; SF12; Short form health questionnaire; Structural equation modeling