Objectives: Knowledge about moderation of the association between hearing loss and depression is scant. We investigated dyslipidemia as a potential moderator of the association between hearing/hearing loss and depressive symptoms.
Design: Cross-sectional study.
Setting: General population-based cohort in France (SU.VI.MAX 2; 2007-2009).
Participants: N= 4,307 adults (mean age = 61.5 ± 6.1 y; 59.6% women).
Measurements: A score ≥ 16 on the Center for Epidemiologic Studies Depression Scale defined presence of depressive symptoms. Mean hearing level for each ear was defined as the pure-tone average of the following thresholds: 0.5, 1.0, 2.0 and 4.0 kHz; the value for the better hearing ear was retained for analysis. Hearing loss was defined as inability to hear at thresholds ≥ 25 dB in both ears. A subjective measure of perceived hearing loss was also used. Serum triglyceride, total-, LDL- and HDL-cholesterol concentrations were assessed in fasting blood samples and established cutoffs were used in multivariable logistic regression models. The interaction between hearing/hearing loss (independent variables) and each of the four lipid parameters was tested.
Results: Even though the interaction tests regarding LDL-, HDL- cholesterol, and triglyceride status were statistically significant, the subgroup analyses revealed few significant and somewhat unexpected findings. In fact, among individuals with low LDL-cholesterol, unlike their counterparts with high LDL-cholesterol, there was an inverse association between hearing level in the better hearing ear and depressive symptoms (OR= 0.94; 95% CI: 0.89-0.99). Regarding the subjective measure of hearing, a few of the dyslipidemia-moderated associations were statistically significant, albeit not all in the predicted direction.
Conclusions: The findings provide some support for moderation of the association between hearing/hearing loss and depressive symptoms by dyslipidemia, with important lipid-specific and hearing measure-specific differences. The results could serve as impetus for future investigations in order to identify and target population subgroups with increased vulnerability to depression in the context of both sensory disability and aging.
Keywords: Cholesterol; aging; depressive symptoms; dyslipidemia; hearing loss; moderators.