Background: We have previously shown women with bipolar disorder have lower bone quantity and quality1, however little else is known about their musculoskeletal health. Thus, we aimed to investigate the association between bipolar disorder and sarcopenia.
Methods: Women with bipolar disorder (n=106) were recruited from southeastern Australia and age-matched controls (n=300), without bipolar disorder drawn from the Geelong Osteoporosis Study. Bipolar disorder was identified using a clinical interview (SCID-I/NP). Maximum handgrip strength was measured using a Jamar dynamometer, appendicular lean mass (ALM) using a Lunar densitometer and body mass index (BMI, kg/m2) was calculated from measured height and weight. Low handgrip strength was considered as <16kg and low lean body mass as <15kg/m2 (ALM adjusted for height). Probable sarcopenia was determined by low handgrip strength and confirmed sarcopenia by the presence of low handgrip strength and low lean mass according to the European Working Group on Sarcopenia in Older People (EWGSOP2) algorithm. Socio-economic status (SES) was determined and information on lifestyle factors and diet obtained via questionnaire. Multiple logistic regression models were used to determine associations between bipolar disorder and sarcopenia while testing for potential confounding.
Results: A higher proportion of women with bipolar disorder met criteria for low handgrip strength [15 (14.2%) vs 21 (7.1%), p=0.027] and low lean mass [6 (5.7%) vs 7 (2.3%), p=0.09] compared to those without bipolar disorder. Forty-six women (11.4%; 43 probable and 3 confirmed) met criteria for sarcopenia. Compared to women without bipolar disorder, women with bipolar disorder were twice as likely to have sarcopenia (OR 2.78, 95%CI 1.47-5.20, p=0.002), independent of age, smoking, physical activity, alcohol, diet quality and SES.
Conclusion: These data suggest women with bipolar disorder are more likely to have sarcopenia. Replication and research into underlying mechanisms are next necessary steps.