Two Key Studies of Prevalence Rates of Smoking (DP IB Psychology)

Key study one: Valente et al. (2005)

Aim: 

• To investigate if popular students are more likely to start smoking and if the association between popularity and smoking varies by gender and/or ethnicity

Participants:

• 1,486 sixth and seventh graders (aged 12-14 years old) in 16 middle schools in southern California

Procedure: 

• Three in-school student surveys were administered: 

  • a baseline, measuring gender, ethnicity, age, grades, susceptibility to smoke, and smoking behaviour

  • a survey two months later, measuring social networks 

  • a 1-year follow-up survey similar to the baseline 

• Susceptibility to smoke was measured as a refusal to commit to not smoke in the future

• Smoking was defined as ‘if you have ever taken a puff or smoked a cigarette’

• Students who were older, White, and had a parent who smoked were more likely to increase their smoking risk

• Popularity was the number of times a student was chosen as a friend by other students in the sample

Results:

• Popularity was associated with increased susceptibility to smoke and smoking, with the most popular students five times more likely to smoke than students who were averagely popular

• Unpopular or isolated students were also likely to be susceptible to smoking or had actually already started smoking 

• The association was stronger for girls than boys, but present for all groups, and not significantly mediated by age, ethnicity or gender

Conclusion:

• Popular students are more visible and so they contribute more noticeably  to the establishment of social norms, like adolescent smoking

• When popular adolescents start to smoke, it sends a signal to other adolescents that smoking is acceptable and even desirable

• Popular students are connected socially to a larger number of students and so they might contribute disproportionately to the process of peer influence on smoking

• Unpopular students’ increased susceptibility may be due to friendships outside the school social network

The most popular students were most likely to be susceptible to smoking or to smoke

Evaluation of Valente et al. (2005)

Strengths

• Valente et al’s quantitative data can be used to inform school health programmes of the need to create a cultural climate in which smoking is not perceived as desirable

• This was a detailed analysis that looked at the possible effects of several variables in order to identify that it was popularity itself that was associated with smoking

Limitations

• The research was conducted in multi-ethnic schools in southern California and so the results may not be generalisable outside of this student population

• This is a correlational study and so the relationship between popularity and smoking has bidirectional ambiguity that needs a more qualitative approach to untangle

Key study two: Strassman et al. (2022)

Aim: 

• To compare the smoking prevalence and lung function of Danish residents (indoor smoking ban since 2007) and Swiss residents (indoor smoking ban since 2010)

Participants: 

• A random sample of 21,045 Danish adults from a sample representative of the general population

• A random sample of 12, 223 Swiss adults from a similar representative population sample

• The mean ages were 61 years for the Danish sample and 51 years for the Swiss sample

• Both samples were 50% female and 50% male

• Over the five years of the experiment over 62,000 Danish and nearly 32,000 Swiss were questioned and tested

Procedure: 

• Natural experiment with a quasi-experimental design 

• Baseline characteristics of the two groups were collected in 2005 and 2006, before either country had banned indoor smoking:

Baseline characteristics of a representative sample of the participants before the Danish nationwide indoor smoking ban in 2007

• Smoking prevalence rates and lung function in a representative sample were measured each year between 2005 and 2010

• These measurements were taken to compare the data for Denmark and Switzerland before and for three years during the indoor smoking ban in Denmark that was introduced in 2007

Results:

• Along with worldwide trends, the prevalence of current smokers in both countries decreased between 2005 and 2010

• The decrease was larger in the Danish (experimental) group compared with the Swiss (control) group, in both males and females, especially after 2007

• Lung function improved in all Danish groups after 2007, even in those who had never smoked

• The Danish sample’s lung function, which had been lower than the Swiss participants’ lung function in 2005, was higher in 2010

Conclusion:

• A nationwide indoor smoking ban is associated with a reduction in smoking and an increase in lung function

• A nationwide indoor smoking ban also improves the lung function of those previously subjected to secondhand smoke

Evaluation of Strassman et al. (2022)

Strengths

• This large-scale study can be used as guidance for policymakers to make evidence-based decisions related to respiratory health in the general population

• The comparison with an appropriate control group suggests evidence for a causal relationship between smoking ban, prevalence and lung function changes

Limitations

• There was no longitudinal lung function data available, which would have allowed a pre–post experiment comparison within the same individuals

• The Swiss and Danish participants may have had unknown differences in health that affected the results, though with such large samples tested over five years, the chances of this making a significant difference are small