BACKGROUND: The interplay between sex, lifestyle choices—such as smoking—and the prevalence and severity of depression is complex and significant. The SLC6A4 gene, which regulates serotonin transport, has been linked to depression. Additionally, smokers tend to exhibit elevated levels of inflammatory biomarkers, including IL-6. However, the relationship between inflammation and depression severity in Nigerian patients has not been thoroughly investigated. This study aims to explore the potential synergistic effects of gene-environment interactions and IL-6 levels on the severity of depression in this population.
METHODS: A total of 164 participants were recruited from 3 randomly selected tertiary facilities in Nigeria, and a 21-item Hamilton depressive rating score (HDRS) was used to measure the major Depressive Disorder (MDD) in the participants to ascertain severity. A score of 0-7 is generally acceptable to be within the normal range, while a score of 8-19 is considered moderate, and 20 or higher is severe. A questionnaire was also used to ascertain respondents’ socio-demographic characteristics and smoking status. Descriptive statistics, chi-square, and t-test were used for the analysis.
RESULTS: The respondents ranged from 18-70 years, with a mean of 30.8 years; 77.4% were females, and 37.5% consumed alcohol. Many 60 (36.6%) of the respondents had a normal HDRS, while 55 (33.5%) and 49 (29.9%) had moderate and severe HDRS, respectively. There were no associations between being a smoker and being depressed (p=0.162; OR=0.456; POR=0.078; 95CI=0.154-1.346).
CONCLUSIONS: The findings of this study indicate that smoking does not significantly influence the occurrence or severity of depression among the participants. Despite the known associations between inflammatory biomarkers and depression, our results suggest that smoking may not exacerbate depressive symptoms in this Nigerian population. Further research is warranted to explore the complex relationships between genetic factors, lifestyle choices, and inflammatory processes in the context of mental health.