Association between low internal health locus of control, psychological distress and insulin resistance. An exploratory study

Abstract

Aim To assess the hypothesis that low internal health locus of control (IHLC) and psychological distress (PD) are associated with insulin resistance. Materials and methods In 2002-2005, a random population sample of 2,816 men and women aged 30-74 years participated (76%) in two municipalities in southwestern Sweden. This study included 2,439 participants without previously known diabetes or cardiovascular disease. IHLC was measured by a global scale and PD was measured by the 12-item General Health Questionnaire. Insulin resistance was estimated using HOMA-ir. General linear models were used to estimate differences in HOMA-ir between groups with low IHLC, PD, and both low IHLC and PD, respectively. Results Five per cent (n = 138) had both PD and low IHLC, 62 per cent of participants (n = 1509) had neither low IHLC nor PD, 18 per cent (n = 432) had PD, and 15 per cent (n = 360) low IHLC. Participants with both low IHLC and PD had significantly higher HOMA-ir than participants with neither low IHLC nor PD (Δ = 24.8%, 95%CI: 12.0-38.9), also in the fully adjusted model (Δ = 11.8%, 95%CI: 1.5-23.0). Participants with PD had significantly higher HOMA-ir (Δ = 12%, 95%CI: 5.7-18.7), but the significance was lost when BMI was included in the model (Δ = 5.3%, 95%CI:0.0-10.8). Similarly, participants with low IHLC had significantly higher HOMA-ir (Δ = 10.1%, 95%CI: 3.5-17.0) but the significance was lost in the fully adjusted model (Δ = 3.5%, 95%CI: -1.9-9.3). Conclusions Internal health locus of control (IHLC) and psychological distress (PD) were associated with insulin resistance. Especially individuals with both PD and low IHLC may need special attention.