The adverse effects of multiple health risk factors have been well-documented; however, still understudied are the effects of early smoking in the context of multiple health risk factors. This study aimed to examine the role of early smoking initiation in relation to several health risk factors, including heavy drinking, physical inactivity, and obesity in later life among ever smokers in the USA. The National Health Interview Survey (NHIS) data from 2006 through 2018 were analyzed. The primary dependent variables were presence of three other risk factors: heavy drinking, physical inactivity, and obesity. The independent variable was the age of smoking initiation. Logit regression models were constructed to evaluate the association between smoking initiation and multiple health risk factors. All analyses were done in 2022. Among US adult smokers, 18.2% started smoking before age 15 (early initiators), 55.9% at ages 15-18 (middle initiators), and 25.9% at age 20 or later (late initiators). Compared to late smoking initiators, the odds of engaging in additional health risk factors increased by 37.3% among early initiators (OR = 1.373, 95% CI = 1.316, 1.432) and 7.7% among middle initiators (OR = 1.077, 95% CI= 1.041, 1.116). Additionally, current smoking was associated with higher odds (OR = 1.369, 95% CI = 1.322, 1.417) of having additional health risk factors compared to former smoking, with one exception: current smokers had lower odds of obesity (OR = 0.566, 95% CI = 0.537, 0.597). Tobacco control programs to prevent adolescents from initiating smoking may have the potential to prevent other health risk factors in adulthood.
Keywords: multiple health risk factor; obesity; physical inactivity; problem drinking; smoking; smoking initiation.