Prenatal Exposure to Tobacco and Cannabis in Six Race/Ethnicity Groups during the First Three Years after Legalization of Cannabis for Recreational Use in California

Abstract

There are known health concerns linked to prenatal tobacco and cannabis exposures. This study aims to objectively determine the level of exposure to tobacco and cannabis in pregnant individuals from six race/ethnicity groups (Black, Hispanic, Asian Indian, Native American, Vietnamese, and White) in the first three years following legalization of recreational marijuana use in 2018 in California. We used a cross-sectional sample of prenatal screening program participants (2018-2020) from southern and central California (N = 925). Exposures were estimated by a lab analysis of cotinine (tobacco) and 11-hydroxy-Δ9-tetrahydrocannabinol (OH-THC, cannabis) in banked serum. Disparities in tobacco exposure were evident, with Black subjects experiencing the highest smoking rate (16%) followed by Native American (10%) and White (8%) subjects, and ≤2% among Hispanic, Asian Indian, and Vietnamese subjects. Environmental tobacco exposure generally showed a similar pattern of exposure to tobacco smoking across race/ethnicity groups. Cannabis detection ranged from 5% among Hispanic subjects to 12% and 13% among White and Black subjects, respectively, and was higher among tobacco users and those exposed to environmental tobacco smoke than those with no cotinine detected. Tobacco and cannabis exposure were generally greatest in younger subjects and those with indices of a lower economic status; however, among Black subjects, cannabis exposure was greatest in older subjects and those with a higher socioeconomic status. Race/ethnicity, age, and socioeconomic factors can inform targeting of high-exposure groups for intervention.

Keywords: 11-hydroxy-Δ9-tetrahydrocannabinol; THC; biomarker; cannabis; cannabis legalization; cotinine; pregnancy; tobacco.

Figure 1

Map of the study region, number, and percent of study subjects in 13 California counties, sample of 925 California prenatal screening program enrollees, 2018–2020.

Figure 2

Smoking rate is defined by cotinine, as per Benowitz et al., 2008 [43] in age and socioeconomic subgroups: Black, Native American, and White high smoking race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 2

Smoking rate is defined by cotinine, as per Benowitz et al., 2008 [43] in age and socioeconomic subgroups: Black, Native American, and White high smoking race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 3

Percent of nonsmokers with cotinine detected in age and socioeconomic subgroups: Black and Native American high-ETS-exposure race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 3

Percent of nonsmokers with cotinine detected in age and socioeconomic subgroups: Black and Native American high-ETS-exposure race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 4

Geometric mean cotinine (ng/mL) in nonsmoker age and socioeconomic subgroups: Black and Native American high-ETS-level race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 4

Geometric mean cotinine (ng/mL) in nonsmoker age and socioeconomic subgroups: Black and Native American high-ETS-level race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 5

Percent of subjects with quantifiable OH-THC in age and socioeconomic subgroups: Black and White high cannabis exposure race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 5

Percent of subjects with quantifiable OH-THC in age and socioeconomic subgroups: Black and White high cannabis exposure race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 6

Geometric mean OH-THC (ng/mL) in age and socioeconomic subgroups: Black and White high-cannabis-level race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 6

Geometric mean OH-THC (ng/mL) in age and socioeconomic subgroups: Black and White high-cannabis-level race/ethnicity groups. Highlighted bars indicate high-exposure subgroups.

Figure 7

Map of study region with location of study subjects (black dots) and cannabis retailers (red dots), sample of 925 California prenatal screening program enrollees, 2018–2020.

Figure 8

(a) Percent of race/ethnicity group with OH-THC detected by proximity to cannabis retailer, sample of California prenatal screening program enrollees, 2018–2020. (b) Geometric mean of OH-THC of race/ethnicity group by proximity to cannabis retailer, sample of California prenatal screening program enrollees, 2018–2020.

Figure 9

(a) Percent of race/ethnicity group with OH-THC detected by density of cannabis retailers, sample of California prenatal screening program enrollees, 2018–2020. (b) Geometric mean of OH-THC of race/ethnicity group by density of cannabis retailers, sample of California prenatal screening program enrollees, 2018–2020.