Background: Alcohol, marijuana and tobacco are the most common recreationally used substances in United States (US). However, unlike alcohol and tobacco, marijuana is an illicit substance. The increasing support for reclassification of marijuana as legal substance necessitates investigating its effect on health. These studies seek to examine the relationship of marijuana and tobacco with metabolic syndrome (a precursor of cardiovascular diseases - the primary cause of morbidities and mortalities).

Method: Data from 2011 public-use linked mortality file of the National Center for Health Statistics, Centers for Disease Control and Prevention, and 2005-2006 & 2011-2012 US National Health and Nutrition Examination Survey was used to estimate the effect of marijuana and tobacco on metabolic syndrome. Odds ratios from logistic regression analyses were determined using four main diagnostic criteria for metabolic syndrome. Odds ratios were compared using: National Cholesterol Education Program Adult Treatment Panel III, World Health Organization, European Group for the study of Insulin Resistance and International Diabetes Federation definitions of metabolic syndrome. Hazard ratios (HRs) for cardiovascular mortality were estimated using cox proportional hazard regression.

Results: Each year of marijuana use was associated with increased odds of metabolic syndrome [OR=1.05 (95% CI: 1.01, 1.09)] and hypertension [OR=1.04 (95% CI: 1.01, 1.07)]. Each additional year of cigarette smoking was associated with increased odds of hypertension [OR=1.03 (95% CI: 1.00, 1.06)] and hyperglycemia [OR=1.03 (95% CI: 1.01, 1.05)]. Adjusted HR for hypertension mortality for marijuana users compared to non-marijuana users was 3.42 (95% CI: 1.20, 9.79) and 1.04 (95% CI: 1.00, 1.07) for each year of marijuana use.

Conclusion: Prolonged years of marijuana use was associated with increased odds of metabolic syndrome and hypertension irrespective of the criteria used to define metabolic syndrome. Our results also indicate that marijuana use is associated with increased risk for hypertension mortality. The association between prolonged use of marijuana and risk of cardiovascular morbidities and mortalities requires further investigation whilst developing global public health policies regarding legalization of marijuana use.