The relationship between early age of onset of initial substance use and engaging in multiple health risk behaviors among young adolescents.

BACKGROUND: Previous research based on problem-behavior theory has found that early age of onset of substance use is associated with engaging in multiple health risk behaviors among high school students. It is unknown whether these relationships begin during early adolescence.
OBJECTIVE: To examine the relationships between early age of onset of cigarette, alcohol, marijuana, and cocaine use and engaging in multiple risk behaviors among middle school students.
METHODS: A modified version of the Centers for Disease Control and Prevention Youth Risk Behavior Survey was administered to 2227 sixth through eighth grade students attending 53 randomly selected middle schools in North Carolina. A Health Risk Behavior Scale was constructed from 16 behaviors, including indicators of violence and weapon carrying; current substance use; nonuse of helmets when biking, in-line skating or skateboarding; not wearing a seat belt; riding with a driver who had been drinking; and suicide plans. Among this sample of middle school students, the scale had a mean (SD) of 4.1 (2.7) (range=O-15), and had a high internal reliability coefficient (alpha(=0.74). The independent variables included first time use of cigarettes, alcohol, marijuana, and cocaine at age 11 years or earlier; actual age of onset of each substance; race and ethnicity; family composition; sex; school grade; academic ranking; and older age for school grade. These data were analyzed with analysis of variance, Spearman r, and multiple linear regression.
RESULTS: All the independent variables were found to be associated (P<.005) with the Health Risk Behavior Scale during the bivariate analyses. When each of these significant variables were entered into a multiple regression model, having smoked at age 11 years or younger accounted for 21.9% of the variation in the Health Risk Behavior Scale. Male sex, early marijuana or cocaine use, older age, lower academic rank, white race, and living in a 1-parent family explained an additional 19.1% of variation in the model (adjusted R2=0.41, P<.001). When the actual ages of onset of the use of substances were analyzed, in order of magnitude; age of onset of smoking; male sex; age of onset of alcohol and marijuana use; age; lower academic ranking; age of onset of cocaine use; white race; and lower academic rating accounted for 52.8% (P<.001) of the variation in the Health Risk Behavior Scale.
CONCLUSION: Even when considering sociodemographic factors, early age of onset of cigarette use was the strongest correlate of the number of health risk behaviors in which these young adolescents had engaged. Early onset of use of other substances was also associated with a clustering of health risk behaviors among this sample of middle school students. The findings suggest that screening for early experimentation with tobacco and other substance use will help identify young adolescents at increased risk for engaging in multiple health risk behaviors.