Department of Family Medicine, Michigan State University, East Lansing, MI, USA.
Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA.
Int J Epidemiol. 2019 Oct 1;48(5):1695-1700. doi: 10.1093/ije/dyz044.
Pre-clinical studies indicate increased food intake and weight gain as cannabinoid effects. Cross-sectional epidemiological studies, however, indicate lower prevalence of obesity among cannabis users. Here, we aim to study the weight-gain research question in the prospectively conducted National Epidemiologic Survey on Alcohol and Related Conditions (NESARC).
NESARC was designed to produce nationally representative estimates for the US population. Participants (aged 18+) completed computer-assisted personal interviews on cannabis use, body weight and height at Waves 1 (W1, 2001-02) and 2 (W2, 2004-05). General linear modelling yields estimates for change in body mass index (BMI) regressed on cannabis-use status, with covariate adjustment based on a conceptual model for BMI determinants (n = 33 000).
At W2, 77% of the participants never used cannabis, 18% had discontinued use ('quit'), 3% were initiates and 2% were persistent users. Estimated W1-to-W2 BMI change shows an increase for all subgroups. Compared with never-users (reference), inverse slope estimates and attenuated change (%) in BMI between W1 and W2 are seen for cannabis-use subgroups: quitters [β = -0.81; 95% confidence interval (CI) = -1.01, -0.60], initiates (β = -0.97; 95% CI = -1.36, -0.57) and persistent users (β = -1.26; 95% CI = -1.81, -0.72).
This new prospective study builds from anecdotes, pre-clinical studies and cross-sectional evidence on inverse associations linking cannabis use and obesity and shows an inverse cannabis-BMI increase association. Confirmatory studies with rigorous cannabis and BMI assays will be needed.
临床前研究表明，大麻的作用会导致摄食量增加和体重增加。然而，横断面流行病学研究表明，大麻使用者的肥胖患病率较低。在此，我们旨在前瞻性开展的全国酒精相关情况流行病学调查（NESARC）中研究体重增加这一研究问题。
NESARC 的设计目的是为美国人口生成具有全国代表性的估计值。参与者（年龄在 18 岁及以上）在第 1 波（W1，2001-02 年）和第 2 波（W2，2004-05 年）时完成了关于大麻使用、体重和身高的计算机辅助个人访谈。通过一般线性模型得出体重指数（BMI）变化的估计值，根据 BMI 决定因素的概念模型进行了协变量调整（n=33000）。
在 W2 时，77%的参与者从未使用过大麻，18%的参与者已经停止使用（“戒掉”），3%的参与者为新使用者，2%的参与者为持续使用者。估计的 W1 到 W2 的 BMI 变化显示，所有亚组的 BMI 均增加。与从不使用者（参考）相比，大麻使用亚组的 BMI 斜率估计值和 W1 到 W2 之间的 BMI 变化幅度呈反比：戒掉者[β=-0.81；95%置信区间（CI）=-1.01，-0.60]、新使用者（β=-0.97；95% CI=-1.36，-0.57）和持续使用者（β=-1.26；95% CI=-1.81，-0.72）。
这项新的前瞻性研究建立在关于大麻使用与肥胖之间存在反比关联的传闻、临床前研究和横断面证据的基础上，表明大麻与 BMI 增加呈反比关系。需要进行更严格的大麻和 BMI 检测的确认性研究。
