Passive smoke exposure trends and workplace policy in the Coronary Artery Risk Development in Young Adults (CARDIA) study (1985-2001)

Lifetime marijuana use and subclinical atherosclerosis: the Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND AND AIMS

Unlike tobacco, the effect of marijuana smoke on subclinical atherosclerosis, a surrogate measure for cardiovascular disease, is not known. This study aimed to determine the association between lifetime exposure to marijuana and measures of subclinical atherosclerosis in mid-life.

DESIGN, SETTING AND PARTICIPANTS

We used data from the US-based Coronary Artery Risk Development in Young Adults (CARDIA) study, a cohort of black and white men and women aged 18-30 years at baseline in 1985-86, with up to seven follow-up examinations over 25 years. A total of 3498 participants in the CARDIA study were included in this study.

MEASUREMENTS

Cumulative years of exposure to marijuana (expressed in 'marijuana-years', with 1 marijuana-year equivalent to 365 days of use) using repeated assessments every 2-5 years for 25 years. Abdominal artery calcium (AAC) and coronary artery calcium (CAC) scores were measured by computed tomography at year 25 examination.

RESULTS

Among 3117 participants with AAC and CAC measurements, 2627 (84%) reported past marijuana use and 1536 (49%) past daily tobacco smoking. Compared with tobacco smokers, 46% of whom reported 10 or more pack-years of use, only 12% of marijuana users reported 5 or more marijuana-years of use and only 6% reported having used marijuana daily. We found a significant interaction between never and ever tobacco users on the association between cumulative marijuana use and AAC (P = 0.05). Among those who never smoked tobacco, cumulative marijuana-years were not associated with AAC or CAC in models adjusted for demographics, cardiovascular risk factors, licit and illicit drug exposure and depression symptoms. However, among ever tobacco smokers, marijuana exposure was associated with AAC and CAC. At 5 marijuana-years of exposure, using AAC = 0 and CAC = 0 as a reference group, the odds ratio (OR) was 1.97 [95% confidence interval (CI) = 1.21-3.21, P = 0.007] for AAC > 0/CAC = 0 and 1.83 (95% CI = 1.02-3.31, P = 0.04) for CAC > 0), regardless of AAC. Tobacco smoking was associated strongly with both AAC and CAC.

CONCLUSION

Marijuana use appears to be associated with subclinical atherosclerosis, but only among ever tobacco users.

Chapter 6: Lung cancer in never smokers: epidemiology and risk prediction models

In this chapter we review the epidemiology of lung cancer incidence and mortality among never smokers/nonsmokers and describe the never smoker lung cancer risk models used by the Cancer Intervention and Surveillance Network (CISNET) modelers. Our review focuses on those influences likely to have measurable population impact on never smoker risk, such as secondhand smoke, even though the individual-level impact may be small. Occupational exposures may also contribute importantly to the population attributable risk of lung cancer. We examine the following risk factors in this chapter: age, environmental tobacco smoke, cooking fumes, ionizing radiation including radon gas, inherited genetic susceptibility, selected occupational exposures, preexisting lung disease, and oncogenic viruses. We also compare the prevalence of never smokers between the three CISNET smoking scenarios and present the corresponding lung cancer mortality estimates among never smokers as predicted by a typical CISNET model.

Occupation as socioeconomic status or environmental exposure? A survey of practice among population-based cardiovascular studies in the United States

Decisions about how occupation is used in epidemiologic research can affect conclusions about the importance of socioeconomic and environmental factors in explaining disparities for outcomes such as cardiovascular disease. A review of practices in the collection and use of occupational data was conducted among population-based cardiovascular studies in the United States. Studies were identified for review from the National Heart, Lung, and Blood Institute website and the biomedical database, Computer Retrieval of Information on Scientific Projects, by use of selected criteria. Data collection instruments and study publications were retrieved and reviewed for 30 of 33 studies (91%). Most of the studies (83%) collected at least descriptive occupational data, and more than half (60%) collected data on workplace hazards. The reviewed studies produced 80 publications in which occupational data were used in analyses, most often as an indicator of socioeconomic status. Authors rarely acknowledged known conceptual and empirical links among socioeconomic status, employment stability, and working conditions. Underutilization of data on workplace conditions was found. Existing data could be used more effectively to examine the contribution of work-related social and environmental conditions to the development of modifiable cardiovascular disease through multiple pathways.