Trends in U.S., past-year marijuana use from 1985 to 2009: an age-period-cohort analysis

Background

We present a formal age–period–cohort analysis to examine if the recent increase in past-year marijuana use among the young is specific to the younger generation or if, instead, it is part of a general increase present across cohorts of all ages. This is the first age–period–cohort analysis of past-year marijuana use that includes adult trends from 2001 to 09.

Methods

Data come from the National Survey on Drug Use and Health, a series of annual, nationally representative, cross-sectional surveys of the U.S. civilian, non-institutionalized population. The analysis focuses on the 25 year time span from 1985 to 2009 and uses the recently developed ‘intrinsic estimator’ algorithm to estimate independent effects of age, period, and cohort.

Results

The recent increase in past-year marijuana use is not unique to the youngest birth cohorts. An independent, positive influence of cohort membership on past-year marijuana use, net of historical period and age effects, is smaller for today's youngest cohorts than it was for the cohorts that came immediately before, and, in fact, is at its lowest level in three decades. The recent increase in marijuana use among the young is more consistent with a historical period effect that has acted across all cohorts. Period and cohort trends differ substantially for Hispanics.

Conclusions

The major forces that drive trends in past-year marijuana use are moving away from cohort-specific factors and toward broad-based influences that affect cohorts of all ages. Strategic public health and policy efforts aimed at addressing the recent increase in past-year marijuana use should do the same.     

Sociodemographic correlates of energy drink consumption with and without alcohol: results of a community survey

Objective

We examined the sociodemographic correlates of energy drink use and the differences between those who use them with and without alcohol in a representative community sample.

Methods

A random-digit-dial landline telephone survey of adults in the Milwaukee, Wisconsin area responded to questions about energy drink and alcohol plus energy drink use.

Results

Almost one-third of respondents consumed at least one energy drink in their lifetime, while slightly over 25% used energy drinks in the past year and 6% were past-year alcohol plus energy drink users. There were important racial/ethnic differences in consumption patterns. Compared to non-users, past-year energy drink users were more likely to be non-Black minorities; and past-year alcohol plus energy drink users when compared to energy drink users only were more likely to be White and younger. Alcohol plus energy drink users also were more likely to be hazardous drinkers.

Conclusions

Our results which are among the first from a community sample suggest a bifurcated pattern of energy drink use highlighting important population consumption differences between users of energy drinks only and those who use alcohol and energy drinks together.     

Age Cohort Differences in the Nonmedical Use of Prescription Zolpidem: Findings from a Nationally Representative Sample

Background

Recent warnings from the FDA have highlighted the potential risks associated with zolpidem use. These risks may be especially acute in nonmedical users of zolpidem, but little work has examined the characteristics of such nonmedical users. This study aims to investigate the correlates of nonmedical use of zolpidem (NUPZ) across the lifespan and potential age cohort-based differences in NUPZ correlates.

Methods

Data from the 2009–2011 versions of the National Survey on Drug Use and Health were used (n = 174,667). Analyses used weighted design-based logistic regressions to examine a set of substance use and mental health correlates within five separate age cohorts and differences in correlate magnitude between these cohorts.

Results

Most examined substance use and mental health variables were significant correlates of NUPZ, though odds ratio (OR) magnitude tended to drop with increasing age. Age-based differences were most apparent for substance use correlates of both lifetime and past year NUPZ, with significantly higher ORs in adolescent nonmedical users. Mental health variables operated more consistently across age, with OR magnitudes that were generally in the same range, regardless of age cohort.

Conclusions

Age-based differences in NUPZ correlates suggest motives may change for NUPZ through the lifespan, though this cannot be established with the cross-sectional data used in this work. Clinicians screening for NUPZ should emphasize such screening in high-risk individuals with substance use and/or mental health problems.