{"doi":"10.1111/add.15685","title":"Combustible tobacco age‐of‐sale laws: an opportunity?","abstract":"There are benefits of raising age-of-sale laws for combustible tobacco only, such as through a Combustible 21 law that would prohibit the sale of combustible tobacco to individuals under 21 years of age but leave open the opportunity to legally purchase e-cigarettes and smokeless tobacco products.. Tobacco 21 (T21), which prohibits retailers from selling tobacco including non-combustible tobacco products such as e-cigarettes and snus to individuals under 21 years of age, became federal law in the United States at the end of 2019, following the adoption of T21 by many states and localities prior to the federal law [1]. T21 has more recently been proposed for England and Europe, where current ages are generally 18 years [2, 3]. In contrast to having a minimum legal sale age (MLSA) of 21 years for all tobacco products, a different approach is to raise the MLSA for combustible tobacco to 21, but leave the MLSA for e-cigarettes and other non-combustibles at 18 as a way to regulate tobacco products proportionate to risk to incentivize harm reduction [4, 5]. This is similar in concept to Sweden and Norway having separate MLSAs for beer and liquor, for example [6]. New Zealand is in the consultation phase of a possible law prohibiting individuals born after January 2004 from purchasing combustible tobacco, but leaving open the avenue for these individuals to legally purchase non-combustibles instead [7]. I and others have previously studied the effect of e-cigarette MLSAs in the United States [8-10] and, after observing how these raised cigarette use among youth, we proposed using a lower MLSA for e-cigarettes than combustible tobacco to encourage youth to use less risky products, as determined by several reviews [11, 12]. Implicit in this recommendation is the scientific opinion that focusing on reducing risks of nicotine products, even at the expense of higher overall nicotine exposure, is the best way to reduce tobacco-related disease and death. T21 was adopted instead and is reducing cigarette use in the United States [13-15], so is an important improvement over the status quo. However, it is reasonable to ask if a Combustible 21 law (C21) would have been better for public health than T21. To simulate the effect of a hypothetical C21 law, I draw from the literature to present a back-of-the-envelope method to predict the effect a hypothetical C21 law would have had in the United States on 18–20-year-olds. This method may also be applicable for estimating effects of other hypothetical policies. Two studies use difference-in-differences methods to find that T21 reduces cigarette use among 18–20-year-olds by 3.1 percentage points (ppt) [13] and 4.0 ppt, respectively [14]. Averaging the effects across these studies suggests a 3.6-ppt reduction. The effect of C21 on cigarette use may be larger than T21 because additional people will use e-cigarettes (which can be legally purchased) instead of cigarettes. Three studies of e-cigarette MLSA law adoption in the United States found that allowing all teenagers to legally purchase e-cigarettes causes, on average, a 0.9-ppt reduction in cigarette use [8-10]. This suggests that the hypothetical effect of C21 would have been a 4.5-ppt (= 3.6 + 0.9) reduction in cigarette use compared to the previously existing law (T18/19). One published study estimates the effect of cigarette taxes on e-cigarette use, finding that a $1 increase in cigarette taxes increases daily e-cigarette use among young adults by 0.48 ppt and decreases daily cigarette use by 0.73 ppt, suggesting a 66% substitution rate [16]. Therefore, a cigarette-only policy causing a 4.5-ppt reduction in cigarette use may cause a 3.0-ppt (4.5 × 66%) increase in e-cigarette use for young adults. This back-of-the-envelope method extrapolates effects of C21. I use the best available estimates from difference-in-differences studies, and do not attempt an exhaustive inclusion of all published estimates. In particular, I do not use estimates for ","journal":"Addiction","year":2021,"id":200535,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":8,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9461,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":393074,"name":"Michael F. Pesko","orcid":"0000-0002-9247-9703","position":0,"is_corresponding":true}],"reference_count":11,"raw_metadata":null,"created_at":"2026-07-18T23:50:48.624274Z","pmid":"34674332","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}