Age at initiation & prevalence of tobacco use among school children in Noida, India: A cross-sectional questionnaire based survey

Material & Methods

Information was collected from students of class 7 to 12 (age: 11-19 yr) studying in different schools of Noida city through a pre-tested, anonymous, closed and open-ended self-administered questionnaire during July- December 2005.

A cluster sample design was used to produce a representative sample of schools. At the first stage, a list of all Private (not funded by the government) and purely government aided schools having grades 7-12 was prepared. At the second stage, the schools were selected randomly from each area. The schools selected were representative of the types of schools in Noida city, viz., private, government girls only, government boys only and co-educational schools. The classes were randomly selected and from each selected class, all students of every alternate section were included. The study was approved by our ethics and review committee of Institute of Cytology & Preventive Oncology (ICMR), Noida. The principals of the schools were informed in writing about the importance of survey. Students were told to participate in the study voluntarily and an informed consent from the students and school authorities was obtained. Children were explained about how to fill up the questionnaire and to provide authentic information. They were assured that all information would be kept confidential. This health questionnaire about tobacco use was prepared based on questionnaire from Global Youth Tobacco Survey (GYTS)8. No changes were made in questions but some were excluded. The questionnaire was provided in English to Private school students and was translated in Hindi for Government school students. The translated version was validated before survey.

The data were collected on socio-demographic profile, occupation and literacy status of their parents. Data were also collected on use of tobacco, age at initiation, smoking habits of parents and siblings, peer influence, reason of initiation of tobacco, places of tobacco consumption, purchase of tobacco for elders at home and teachers, etc. ‘Ever use of tobacco’ was defined as the use of tobacco even once including current tobacco use9. Tobacco consumption was broadly classified into three categories: smoking, chewing and more than one form of tobacco use. Tobacco smoking includes cigarettes, beedis and others such as hookah, chillum, ganja, etc. Smokeless tobacco use includes Gutka, Khaini and Zarda1011 (Appendix).

The target sample size calculated was 5600, keeping in mind the least prevalence of tobacco use as 6.0 per cent, a relative precision of 10 per cent and confidence interval of 95 per cent. A total of 5646 questionnaires were distributed to all eligible students in 17 schools of Noida. Those students who refused to participate were asked to remain in the class and not to disturb the participants.

Data were analyzed using Epi-info 6.04 D os0 version (free software downloaded from internet) and SPSS (version 11). Differences in proportions between the various groups viz., between girls and boys; between tobacco users and never users and differences in the type of tobacco used based on the type of schools (Private schools vs. Government schools) were tested using Pearson’s Chi-square test or Fisher’s exact test, as appropriate along with Odds ratio and 95 per cent confidence intervals (CIs). To compare the mean age of study variables, Students t-test was applied and alpha was set at 0.05.

Results

A total of 4786 students (85.0% response rate) filled the questionnaire (boys: 49.3% and girls: 50.7%); of the remaining 860 students, some were absent on the day of collection while the remaining declined to participate because of parental refusal. The mean and median age for students was 14.8 ± 1.6 and 15 yr respectively. Almost an equal number of boys 2360 (49.3%) and girls 2426 (50.7%) responded and there was no difference in their mean ages (boys: 14.8 ± 1.6 and girls: 14.8 ± 1.5 yr). More than 90 per cent of the students belonged to Hindu families. The predominant occupation of the father was service, more than 55 per cent of them had educational status of high school and above and fathers of only 3 per cent students were illiterate. In contrast, majority of the mothers (73%) were housewives, about 50 per cent had studied up to or beyond high school and as high as 17 per cent were illiterate. About 70 per cent of responders resided in urban areas while 30 per cent resided in semi-urban settings. Government school students comprised 44 per cent (n=1914) of the subjects, while 2872 (56%) studied in private schools.

Prevalence of ever use of tobacco:‘Ever tobacco use’ in any form (smoking or chewing tobacco) was found in 537 (11.2%) students, of which 197 (4.1%) were current tobacco users. ‘Ever smokers’ comprised 419 (8.8%) [current smokers 148 (3.1%)], ‘ever tobacco chewers’ comprised 219 (4.6%) students (current tobacco chewers 1.9%). ‘Exclusive ever smokers’ comprised 6.6 per cent, ‘exclusive ever tobacco chewers’ 118 (2.5%) and ‘ever both smoking and tobacco chewing’ 101 (2.1%). Overall, the prevalence of tobacco use in any form was significantly more in boys as compared to girls (P<0.05). ‘Exclusive ever smoking’ was found to be equally common among boys and girls while ‘exclusive ever chewing’ and both habits (‘ever smoking and tobacco chewing’) were significantly more common among boys as compared to girls (Table I).

Among all the students, 5.3 per cent (256 of 4786) had ever smoked cigarette exclusively (boys: 5.7%, girls: 5.0%). Girls had ever used zarda (10 of 2426; 0.4%) and smoked beedis (61 of 2426; 0.4%) more frequently than boys (52 of 2360; 2.2%) while among boys khaini chewing (44 of 2460; 1.9%) and habit of ‘chewing multiple products’ (46 of 2460; 1.9%) was more prevalent. When different smoking and chewing habits were analyzed independently, it was found that types of smoking and chewing tobacco did not differ according to gender (Table II).

‘Ever use of tobacco’ was found to be more in government school boys (13.4%) in comparison to private school boys (11.7%) whereas a reverse pattern was observed amongst girls (government:8.6%, private: 11.8%; P<0.01). ‘Exclusive smoking’ was found to be significantly more prevalent among both boys and girls of private schools in comparison to government school students (private: 121, government: 58 P<0.05).

Age at first use (initiation): There was no significant gender difference in the age of uptake of overall tobacco habits (Table III). Nearly 70 per cent of boys and 80 per cent of girls up to the age of 15 yr initiated the habit of tobacco before the age of 11 yr. Among younger boys (≤15 yr), significantly more numbers initiated tobacco habits before 11 yr of age as compared to older boys (>15 yr) (P<0.01). Similar trend was observed in girls also (P<0.01). The uptake of tobacco habits ‘before age 11 yr’ was found to be 1.8 times earlier among girls than boys (P<0.01, CIs: 1.19-2.69). A statistically significant linear trend of age at initiation of any tobacco habit was observed in the age group of up to 15 yr, among both boys and girls (P<0.05 and P<0.01 respectively) (Table IV). Thirty five per cent of private school students initiated tobacco chewing before the age of 11 yr while only 14 per cent government school students initiated it at this age (P<0.05) (Table V).

Discussion

Majority of the tobacco related deaths occur in developing countries where problem of tobacco is assuming alarming proportions. A study at Gujarat State, India, showed a downward shift in age of initiation of this habit which is a matter of serious concern12.

The prevalence of tobacco use among school students in different States of India has been reported to vary from 1.9 per cent (Delhi) to 75.3 per cent (Mizoram)3413–18.The prevalence of ‘ever use of tobacco’ in the present study was 11.2 per cent (boys: 12.2%, girls: 10.2%) which is much lower than the 37.2 per cent (boys: 39.2%, girls: 31.9%) reported by GYTS performed in Uttar Pradesh5. Lower prevalence inNoida city may actually reflect the rates of its neighbouring city of Delhi, as a large proportion of school students in Noida are residents of Delhi. Though tobacco use is on rise among girl students, we found the habit to be still a little less prevalent in girls than in boys. This observation is corroborated by other Indian studies61018. The overall prevalence of ‘ever smoking’ (8.8%) in the present survey was also quite low in comparison to studies done in Haryana (12.0%)18 and Jamnagar (14.6%)19. According to GYTS 1999-2001, most countries viz. AFRO, AMRO/PAHO, EMRO, EURO, WPRO and SEARO also reported higher prevalence of ‘ever smoking’ varying from 10.2 to 73.6 per cent except Nepal where lower prevalence rate (6.5%) was reported8.

‘Ever use of tobacco’, particularly the use of smokeless tobacco products, was found to be more common in government school boys in comparison to private school boys, whereas this pattern was reverse amongst girls. This has considerable public health implication as it is known that people change over from smokeless form to smoking over a period of time. Our findings are in accordance with the results of Mathur et al20. Low socio-economic status of government school students may be responsible for this, since being relatively inexpensive and readily available, these children often see tobacco as an alternative to food1021.Also chewing of these products is considered less harmful than smoking. Increasing practice of tobacco use in private schools may be attributed to peer pressure, rising influence of western culture, rapid urbanization, increased disposable income in the affluent families, tobacco use by their role models, parental habits, media promotion and best friends.

In the present study, though no significant differences were observed in the overall mean ages of initiation for ‘ever smokers’ and ‘ever tobacco chewers’, notable gender differences were found. The mean age at initiation of ‘exclusive smoking’ was significantly lower in girls as compared to boys. Ageat onset of smoking in our study was consistent with that observed in developed countries. The studies conducted among U.S. youths for ‘smoking by race and ethnicity’ and in Jerusalem school children also found the mean age at initiation to be around 12 yr2223. A little higher age of initiation was found among Chinese Americans (boys: 12.8, girls: 13.1 yr), Non-Hispanic white minors (boys: 12.5, girls: 13.0 yr) and South African students (males: 15.16 and females: 14.98 yr)23–25.Among the Indian studies, the mean age of initiation of tobacco use has been found to vary from 8 to 15 yr41015. The majority of the tobacco users worldwide have reportedly first tried tobacco prior to age 186, some starting as young as 10 yr26.Our survey reflects a recent downward shift in age at uptake of tobacco habit among children. In a study from Kerala the mean age at initiation was 10.7 yr for boys ≤13 yr and 13.2 yr for boys ≥16 yr at the time of survey27. Even though tobacco use by small children and particularly girls is thought to be culturally unacceptable in Indian society13, in our study as many as 31 per cent of ever tobacco using students started using tobacco before the age of 11 yr. This figure is lower than that reported from the north-eastern States of India and GYTS report from Uttar Pradesh, where over 65 and 72 per cent of students respectively reported uptake at or before 10 yr of age513. Similar results have been reported from small studies done in rural areas of Gujarat, Tamil Nadu, Karnataka and Goa where one third to one half of children under the age of 10 yr experimented with smoking or smokeless tobacco in some form1628. In a study conducted in Nairobi, 72 per cent students reported tobacco initiation between age 12 and 16 yr29. On the other hand, according to National Youth Tobacco Surveillance, United States, 4.9 to 14.3 per cent middle school and 4.9 to 14.3 per cent high school students of different States started cigarette smoking before 11 yr of age; for smokeless tobacco use, the figures varied from 1.2-10.2 per cent for middle schools and 1.3- 8.7 per cent for high schools30.

The response rate was 85 per cent in the present study. Since the characteristics of non-responders (15%) who were present in the class but did not answer the questionnaire were not studied, it would be an important limitation in interpretation of the findings of the study. Use of self-reported age of onset from a cross-sectional data is another limitation. Longitudinal studies have demonstrated that older adolescents tend to report a later age of smoking onset than younger ones17.The smoking behaviour mentioned in the questionnaire may differ from the actual smoking habit. The potential bias resulting from some students being absent on the day of survey is another limitation as these students might have higher rates of health risk behaviours.

In conclusion, the observations of the present survey indicate a downward shift in the age at uptake of tobacco habit by children and a rising prevalence among girls. More such surveys need to be carried out in other large cities of the country in order to build comprehensive database for future policy decisions on anti-tabocco campaigns.