The new study now appears in the journal PLOS ONE.
In it, Prof. Levine and colleagues explain that there are clues in existing research that point to smoking as a predisposing factor to depression.
For instance, depression tends to be twice as likely among people who smoke than those who do not, but it is not yet clear which causes which. Some researchers, however, believe that smoking may lead to depression, not vice versa.
What is more, other studies have found that people who had never smoked generally have a better health-related quality of life (HRQoL), as well as less anxiety and depression.
So, to help shed some light on the matter, Prof. Levine and team decided to study the association between HRQoL and smoking among students in Serbia. Few studies have looked into this association in low- and middle-income countries.
However, more than 25% of people living in Serbia and other Eastern European countries smoke, which is another reason that studying this subject in this population is of interest. Furthermore, about a third of students in Serbia smoke.
Studying smoking and mental health
The new study included data from two cross-sectional studies that gathered information from two universities: the University of Belgrade and the University of Pristina. The former has around 90,000 students, and the latter has around 8,000.
The participants provided information about their social and economic backgrounds â€” such as their age, social status, place of birth, and parentsâ€™ education â€” as well as information on any preexisting chronic conditions. They also provided information about their habits and lifestyle, such as smoking status, alcohol use, exercise levels, and eating habits.
The researchers classed people who smoked at least one cigarette per day or 100 cigarettes in a lifetime as â€œsmokersâ€ for the purposes of this study.
To assess the studentsâ€™ HRQoL, Prof. Levine and colleagues asked them to fill in a questionnaire comprising 36 questions across eight dimensions of health. These were:
- physical functioning
- role functioning physical
- bodily pain
- general health
- social functioning
- role functioning emotional
- mental health
For each of these parameters, a score between 0 and 100 reflected how the interviewee perceived their own mental and physical health.
The team also used the Beck Depression Inventory (BDI) to assess the studentsâ€™ depressive symptoms. The BDI has 21 items, each with a score from 0 to 3.
According to the BDI, a final score of:
- 0â€“13 represents â€œno or minimal depressionâ€
- 14â€“19 ranks as â€œmild depressionâ€
- 20â€“28 represents â€œmoderate depressionâ€
- 29â€“63 ranks as â€œsevere depressionâ€
Tobacco negatively impacted mental health
Overall, the study found that having a higher BDI score was associated with smoking. Furthermore, the students who smoked were two to three times more likely to have clinical depression than those who had never smoked.
At the University of Pristina, 14% of those who smoked had depression, whereas only 4% of their non-smoking peers had the condition. Among those who smoked at the University of Belgrade, 19% had depression, compared with 11% of those who did not smoke.
Those who smoked also consistently had more depressive symptoms and poorer mental health, as reflected in the â€œvitalityâ€ and â€œsocial functioningâ€ parameters.
Prof. Levine adds, â€œOur study adds to the growing body of evidence that smoking and depression are closely linked.â€
â€œWhile it may be too early to say that smoking causes depression, tobacco does appear to have an adverse effect on our mental health.â€
Prof. Hagai Levine
He goes on to warn against the perils of smoking, and he encourages policymakers to help prevent these dangers.
â€œI urge universities to advocate for their studentsâ€™ health by creating â€˜Smoke- Free Campusesâ€™ that not only ban smoking on campus but tobacco advertising, too.â€
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