BACKGROUND AND AIMS Uruguay and Chile have the highest levels of marijuana use in Latin America and experienced consistent increases over the last 2 decades. We aim to calculate separate age-period-cohort (APC) effects for past-year marijuana use in Uruguay and Chile, which have similar epidemiologic and demographic profiles, but diverging paths in cannabis regulation. DESIGN Age, period and cohort study in which period and cohort effects were estimated as first derivative deviations from their linear age trend, separately by country and gender. SETTING Uruguay and Chile. PARTICIPANTS General population between 15 and 64 years of age. MEASUREMENTS Past-year marijuana use from household surveys with five repeated cross-sections between 2001-2018 in Uruguay (median n=4,616) and 13 between 1994-2018 in Chile (median n=15,895). FINDINGS Marijuana use prevalence in both countries peaked at 20-24 years of age and increased consistently across calendar years. Period effects were strong and positive, indicating that increases in use were evident across age groups. Relative to 2006 (reference year), Chilean period effects were about 48% lower in 1994 and about four times higher in 2018; in Uruguay, these effects were about 56% lower in 2001 and almost quadrupled in 2018. We observed non-linear cohort effects in Chile, and similar patterns in Uruguay for the overall sample and women. In both countries, marijuana use increased for cohorts born between the mid-1970s and early 1990s even in the context of rising period effects. Prevalence was consistently larger for men, but period increases were stronger in women. CONCLUSIONS Age-period-cohort effects on past-year marijuana use appear to have been similar in Chile and Uruguay, decreasing with age and increasing over time at heterogeneous growth rates depending on gender and cohort. Current levels of marijuana use, including age and gender disparities, seem to be associated with recent common historical events in these two countries.

中文翻译：

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两个拉丁美洲国家的大麻使用趋势：年龄、时期和队列研究

背景和目标 乌拉圭和智利的大麻使用量在拉丁美洲最高，并且在过去 20 年中持续增长。我们的目标是计算乌拉圭和智利过去一年使用大麻的不同年龄-周期-队列 (APC) 效应，这两个国家具有相似的流行病学和人口统计学特征，但大麻监管的路径不同。设计 年龄、时期和队列研究，其中时期和队列效应被估计为其线性年龄趋势的一阶导数偏差，分别按国家和性别。设置乌拉圭和智利。参与者 15 至 64 岁的一般人群。测量 来自乌拉圭 2001-2018 年（中位数 n=4,616）和智利 1994-2018 年（中位数 n=15,895）13 个重复横断面的家庭调查的上一年大麻使用情况。发现这两个国家的大麻使用流行率在 20-24 岁达到峰值，并且在历年中持续增加。周期效应强烈且积极，表明各年龄组的使用率明显增加。相对于 2006 年（参考年），智利时期的影响在 1994 年降低了约 48%，在 2018 年增加了约四倍；在乌拉圭，这些影响在 2001 年降低了约 56%，在 2018 年几乎翻了两番。我们观察到智利的非线性队列效应，以及乌拉圭整体样本和女性的类似模式。在这两个国家，即使在时期效应上升的情况下，1970 年代中期至 1990 年代初出生的人群的大麻使用量也有所增加。男性的患病率一直较高，但女性的经期增长更快。结论 在智利和乌拉圭，年龄-时期-队列对过去一年大麻使用的影响似乎相似，随着年龄的增长而下降，并随着时间的推移以不同的增长率增加，取决于性别和队列。目前的大麻使用水平，包括年龄和性别差异，似乎与这两个国家最近的共同历史事件有关。