Examining the Relationship Between Age of Offer and Age of Use of Cigarettes, Alcohol, and Marijuana in a Diverse International Sample

Introduction:

Alcohol, tobacco, or other drug exposure among youth represents an environmental determinant of future use behaviors. Anthony and colleagues’ two-stage developmental model of drug use notes that exposure is prerequisite of use (2002). Data from the US on progression from offer to use is rich for cigarettes, alcohol, and marijuana. This data indicates that age of offering is a key determinant of use: seeming to peak at approximately 13 years old for marijuana. However, little is known about offering and use in other cultures.   

Methods:

A multistage stratified cluster design produced a random sample of 1,814 youth in grades 7-11 in 14 schools (six private and eight public) in two school districts in Caracas, Venezuela. The mean age of the participants was 15.5 years and 53.3% were female. Over half lived in the poorest housing area (55.7%) and 30% reported either their father or mother as having finished a post high school degree (e.g., vocational, technical, university). Data were collected using a standardized self-administered questionnaire that was pilot tested using a sample of adolescents and teachers in Venezuela to establish the face validity of the instrument and to ensure cultural fit and accuracy before its implementation. A series of zero-inflated Poisson regressions were run to check the nonlinear effect of age of first substance (cigarettes, alcohol, marijuana) use offer on age of first use for the same substance.

Results:

The older an adolescent was when they were offered cigarettes, the older they were when they used for the first time, no nonlinear effect. There was a marginal nonlinear effect of age of being offered cigarettes, with earlier ages and later ages showing less risk and ages from 9-11 showing increased risk of using cigarettes. There was a nonlinear effect of age of offer on age of alcohol use. With older ages of offer resulting in closer ages of use. A nonlinear effect in the same pattern as cigarettes existed for alcohol use. Marijuana age of use showed a similar nonlinear effect of age of being offered as alcohol. There was no effect for use of marijuana.

Conclusion

Our data suggest that a) the relationship between being offered a drug and age at first use is not a linear relationship; and b) the peak age (age of greatest risk) in which receiving an offer to use a substance influences use of that substance is lower in Venezuela than what has been found in US samples. Cultural variations in areas such as stigma against illicit drugs and the use of alcohol at family functions that help explain these differences will be developed and implications for prevention interventions will be discussed.