Research Projects

Tobacco Use Research – Prof Olalekan Ayo-Yusuf

Tobacco Use Research – Prof Olalekan Ayo-Yusuf

Prof Olalekan Ayo-Yusuf

Title of Project:

Tobacco use among adolescents in the Limpopo province, South Africa

Highlights of the Project:

In line with our primary objective, we found that there were significant individual differences in the rate of progression from being non-smoker/occasional smoker to becoming a regular smoker over a four-year period of follow-up. The most significant direct predictor of progressing at a faster rate was reporting at baseline, a low confidence of being able to say ‘no’ to offer of a cigarette from a close friend, which in turn was associated with having many close friends and household members that smoke.  In-depth interviews with some life orientation (LO) educators suggested that the tobacco use prevention programme we had tested was not completely delivered because the materials were not examinable by the educational authority, even though it had more content with regards skills to prevent risk behaviours than the usual textbooks. This may explain why this programme did not show a significant effect on tobacco use prevention, even in the long-term.

Scientific Progress Report

In line with our primary objective, we have so far performed a latent growth analysis using the structural equation modelling (SEM) approach to determine if there were significant individual differences in smoking trajectory and determine the role of smokeless tobacco in determining how adolescents advance in their tobacco use trajectory and any modifying role of ability to cope with stress as measured on the sense of coherence scale. While, the high attrition rate from Grade 10 to Grade 12 (a problem well documented in lay press in South Africa), we restricted our analysis to a sample up to Grade 11 (average age 18yrs) in order to have adequate sample size (n=944). Future analyses would be establishing classes/types of adolescent smokers.

Although we previously found smokeless tobacco (SLT) to be associated with smoking initiation among never smokers, using this robust statistical analysis we determined the rate at which adolescents progress from non-smoker/occasional smoker to becoming a regular smoker was not directly associated with SLT use or the adolescents’ sense of coherence (SOC). However, SLT use at baseline and having a lower SOC was indirectly associated with progression rate through increasing the risk of keeping more friends that smoke, which in turn was associated with having a low confidence to be able to refuse cigarette offer from a close friend. It is pertinent to note that the single most significant factor associated with faster progression from being a non-smoker to becoming a regular/frequent smoker was expressing at baseline a low confidence to refuse cigarette offer from a close friend (i.e. cigarette offer self-efficacy).

We also found that reporting to have a household member smoking, especially if they smoke inside the house, were not only associated with increased susceptibility to smoking, but was also associated with greater likelihood of keeping more friends that smoke. These findings have increased our understanding of the potential role of parental smoking on adolescent smoking in South Africa and emphasise the need for future prevention interventions to involve adolescents’ family members/guardians for it to be effective. Furthermore, that providing social resistance skill, such as high level of assertiveness should remain an important component of future tobacco use prevention interventions among adolescents as they become young adults.

Our study of medical students indeed also showed that smoking was associated with socializing. We further explored other known risk factors for Head and Neck cancer and in particular sexual risk behaviours which has been associated with risk for HPV infection – an important risk factor for oro-pharyngeal cancers. Given the mediating role of perceive vulnerability to disease risk in taking preventive measures, we investigated the role of various channels of delivery of preventive messages on increasing perceived vulnerability to HIV infection.

Although, classroom instructions and TV/radio were the most frequently reported source of reliable HV information by the adolescents, they were not as likely to increase perceived vulnerability as having reported having received their information from parents/older adults in the family, a school counsellor/class teacher or from clinic brochure – all privately shared information as opposed to transient auditory or visual messages from classroom instructions or TV/radio. We also found that although sexual activity increased over the period from Grade 8 to Grade 12, safe sexually practices such as use of condoms increased over this period.

This is the first longitudinal study examining these relationships in South Africa.

Consistent with risk perception theory, we also determined the level of interest of adolescents in genetic testing for nicotine dependence susceptibility and found that only a quarter of adolescents were interested in such test. Level of interest was particular higher among those with more educated mothers. The implication is that genetic research and application of future clinical usefulness of such test in tailoring dependence treatment will require public education.

Non-Scientific Progress Report:

In furthering the objectives of this project, we continued to studied factors associated with varying rates of adolescents’ progression from being a non-smoker or occasionally smoker to becoming a regular or frequent smoker. Using a more sophisticated statistical approach, we provide a better understanding of the factors associated with this progression rate, in particular the role of snuff use and the disposition to cope with stress as measured on the sense of coherence (SOC) scale and depression vulnerability questionnaire item.

Although we previously found snuff to be associated with smoking initiation among never smokers, using this statistical analysis we determined the rate at which adolescents progress from non-smoking/occasional smoking to regular smoking was not directly associated with snuff use or the adolescents’ sense of coherence (SOC). However, snuff use at baseline and having a lower SOC was indirectly associated with faster progression by increasing the risk of keeping more friends that smoke, which in turn was associated with having a low confidence to be able to say ‘no’ to a cigarette offer from a close friend. It is pertinent to note that the single most significant factor associated with faster progression from being a non-smoker to becoming a regular/frequent smoker was expressing at baseline a low confidence to be able to say ‘no’ to cigarette offer from a close friend.

We also found that reporting to have a household member smoking, especially if they smoke inside the house, were not only associated with adolescents’ lower level of commitment to a smoke-free lifestyle, but was also associated with a greater likelihood of keeping more friends that smoke. These findings have increased our understanding of the potential role of parental smoking on adolescent smoking in South Africa and emphasise the need for future prevention interventions to involve adolescents’ family members/guardians for it to be effective.

Furthermore, that providing social resistance skill, such as high level of assertiveness should remain an important component of future tobacco use prevention interventions among adolescents as they become young adults. Our study of medical students indeed also showed that smoking was associated with socializing.

We further explored other known risk factors for Head and Neck cancer and in particular sexual risk behaviours which has been associated with risk for HPV infection – an important risk factor for oro-pharyngeal cancers. Given the mediating role of perceive vulnerability to disease risk in taking preventive measures, we investigated the role of various channels of delivery of preventive messages on increasing perceived vulnerability to HIV infection.

Although, classroom instructions and TV/radio were the most frequently reported source of reliable HV information by the adolescents, they were not as likely to increase perceived vulnerability as having reported having received their information from parents/older adults in the family, a school counsellor/class teacher or from clinic brochure. We also found that although sexual activity increased over the period from Grade 8 to Grade 12, safe sexually practices such as use of condoms increased over this period. This is the first long-term study examining these relationships in South Africa.

Congress abstracts

1. Rantao M, Ayo-Yusuf OA. Adolescents’ sources of HIV information and perceived vulnerability to HIV: a longitudinal study. Poster presented at the 2011 conference of the Public Health Association of South Africa (PHASA): 29th Nov 2011.

2. Rantao M, Ayo-Yusuf OA. Predictors of South African adolescents’ commitment to a smoke-free lifestyle: a one-year longitudinal study. Accepted for oral presentation at the 15th World Conference on Tobacco or Health, Singapore to be held 19-24 March 2012.

Manuscripts

We have four manuscripts in preparation.

1. Rantao M, Ayo-Yusuf OA. Perceived sources of reliable HIV information and Adolescents’ self-perceived susceptibility to HIV: a longitudinal study.

2. Ayo-Yusuf OA, Connolly GN. Role of Smokeless tobacco in smoking initiation and cessation among South African adolescents.

3. Ayo-Yusuf OA, Olutola BG, Jansen van Rensburg E, Audrain-McGovern J. Interest in genetic testing for Nicotine Dependence susceptibility among South African adolescents.

4. Ayo-Yusuf OA, Okagbare TE. Clustering of perceived overweight with poor diet and poor oral health among a population of South African Adolescents.

Publications

1. Rantao M, Ayo-Yusuf OA. Dual use of cigarettes and smokeless tobacco among South African AdolescentsAmerican Journal of Health Behaviors 2012; 36: 124-133.

2. Senkubuge F, Ayo-Yusuf OA, Louwagie GMC, Okuyemi KS.  Water-pipe and smokeless tobacco use among medical students in South AfricaNicotine & Tobacco Research (in press).

3. Ayo-Yusuf OA, Okagbare TE, Ayo-Yusuf IJ. Prevalence and socioeconomic disparities in fissure sealant placement among adolescents in Limpopo, Province, South Africa.

South African Dental Journal 2011; 66: 380-383.

4. Ayo-Yusuf OA, Booyens S. Principal motives for tooth-brushing in a population of South African adolescents: implications for oral health promotionSouth African Dental Journal 2011; 66: 174-8.

Please summarise how you believe this project is of value in the struggle against cancer:

This project is beginning to bring forth evidence that may be used to inform appropriate design of interventions for multiple cancer risk behaviours among adolescents in South Africa, especially those of low socio-economic status.  Also, the fact that it provides an opportunity for a black female South African to obtain a MPH degree and now employed at the University is further contribution to capacity-building towards sustained fight against cancer in South Africa.

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