Introduction

Since the 1960s, migration to the United States (US) has more than quadrupled with immigrants representing 13.7% of the population (Budiman et al., 2020). This is expected to double in the coming decades. Historically, the life circumstances that surround the immigration process to the US has involved adversity, struggle, and blocked opportunities. According to arguments from mainstream social science theories based on data from native-born citizens, enduring such hardships can increase the likelihood of developing a host of poor health outcomes (Piquero, 2008). However, recent research has reported that immigrants in the US may actually demonstrate more resilience to adversity and disadvantage, compared to native-born citizens as immigrant status often protects against antisocial and substance abuse behaviors (Bersani, 2014; Fenimore et al., 2019; Vega et al., 1998). This finding has been termed the “immigrant paradox.”

While studies from sociology, epidemiology, and social work have documented that immigrants often report lower rates of mental health and substance use (Bowe, 2017; Ortega et al., 2000), the mechanisms involved in this paradox are not well understood. It has been suggested, for example, that immigrants carry a unique set of protective and risk factors—generally marked by what immigrant generation they belong to—that guide their social, behavioral, and health adaptations (Fenimore et al., 2019). The immigrant experience is often underscored by the acculturative process that requires specific social adaptations including conforming to linguistic standards (e.g., learning English, integrated accent), cultural and behavioral expectations, and Anglo identities (Alamilla et al., 2019; Phinney, 1992; Portes & Zhou, 1993). As a result of these adaptations, and considering the range of heterogeneity in immigrant backgrounds (e.g., country of origin, legal statuses, religion, skin color), the immigrant experience may produce varying levels of stress. As Lee et al. (2013) suggest, these stressors may result in maladaptive coping strategies, such as alcohol use for some individuals. Indeed, prior research has reported that, on average, immigrants in the US report lower levels of alcohol use, but there are many who engage in high levels, thus leaving much unknown about the underlying factors that contribute to this observed heterogeneity (e.g., Alamilla et al., 2019; Gil et al., 2000; Green & Maggs, 2018; Niño et al., 2017; Vega et al., 1998; Waldron et al., 2021). One possible factor that may be involved is resting heart rate (RHR)—a measure of cardiovascular functioning. High and low levels of RHR may impact levels of adaptive alcohol use to the acculturation experience (Yakushko et al., 2008).

One reason to suspect this is based on prior research examining links between RHR, antisocial behavior, depression, and substance use. For antisocial behavior, studies find that the association between adverse life experiences and antisocial behavior is partly mediated or moderated by lower levels of RHR (Choy et al., 2015; Fagan et al., 2017; Raine et al., 2014). The opposite is observed when examining the association between stress and mental health, whereby individuals with higher RHR are more likely to self-medicate with alcohol and illicit substance use (Latvala et al., 2016). While most of these studies examine relations between variables continuously, many of the associated outcomes and results tend to be grouped into extremes of the RHR distribution. For example, Choy et al. (2017) found that when considering the magnitude of the difference for RHR taken at age 11, RHR was notably lower for offenders than nonoffenders averaging about eight beats per minute (BPM) lower for offenders. Another example is seen in Latvala et al.’s (2016) work, which reported that ten-unit increases in RHR produced notable increases in risk for a variety of psychiatric disorders. Among those on the higher end of their RHR sample distribution, individuals with resting heart rates above 82 BPM—or ten units above their sample mean—were at greater risk of anxiety, obsessive–compulsive disorder, and schizophrenia. As such, there are grounds to further investigate the tails of the RHR distribution (one standard deviation above the mean and one standard deviation below the mean) as they may reveal additional patterns associated with individual differences in deleterious life outcomes, such as unhealthy substance use habits.

Taken together, it appears that RHR may operate as a source of risk and resilience depending on the stressor and outcome under investigation. To date, however, no study has examined the role of RHR on the association between the immigrant paradox and alcohol use. As such, the current study focuses on examining the extent to which RHR conditions the relationship between the immigrant experience and frequency of alcohol use, as well as drunkenness. In doing so, we aim to extend the existing body of research on how immigrants cope with the acculturation experience by possibly identifying a biological mechanism involved in explaining heterogeneity in response to this process.

The Immigrant Experience and Alcohol Use

Prior literature surrounding the immigrant experience largely suggests that immigrant status acts as a protective factor against a wide range of negative outcomes endured in later developmental periods (Bersani, 2014; Fenimore et al., 2019; Green & Maggs, 2018). The concept of acculturation and its subsequent personal and social consequences stems from a theory known as segmented assimilation (Portes & Zhou, 1993). This is widely regarded as one of the most influential theoretical frameworks for understanding and describing why behaviors differ between immigrant groups. Following the 1965 Immigrant and Nationality Act, the tide of immigration changed and emigration to the US became much more feasible. At this time, immigrant segments had begun to greatly diversify and so did the challenges faced by the children of immigrants. In Portes and Zhou’s (1993) original postulation, the general consensus among scholars and the public was that to acculturate was to seek acceptance among the native-born in order to gain access to social and economic opportunities. Their principal challenge was that the assimilation process had become segmented (p. 82). That is, immigrant groups assimilate differently and into different sectors of US society. As Stepick and Stepick (2010, p. 1160) summarized, “at the most elemental level, segmented assimilation simply means that not all children of immigrants assimilate or integrate in the same fashion or achieve the same outcomes.” They argued how immigrants, and their children, assimilate via the acculturation process was of great importance to understanding individual adaptations to US society.

The acculturation process is multifaceted and marked by a series of background factors that could contribute to stress like what immigrant generation one belongs to, ethnic background, parental education, family structure, gender, legal status, and community context (e.g., ethnic enclaves). While many of these features also condition coping behaviors among the native-born, how immigrant groups adapt or cope to the emergent acculturation stress depend on many unique vulnerabilities such as legal status, skin color, the location or where an immigrant settles (e.g., inner city), economic opportunity structures, social networks, disparate social and legal treatment, perceived discrimination, and fitting into multicultural contexts (Finch & Vega, 2003; Gil et al., 2000; Kessler et al., 1999; Niño et al., 2017; Waldron et al., 2021). While modes of acculturation differ (e.g., selective acculturation, see Waters et al., 2010), a method of examining the immigrant experience and its acculturative auxiliaries are through observed immigrant-indicators, primarily membership into any given immigrant generation (e.g., first-generation, second-generation). These primarily rely upon if an individual and their parents were born in the US or abroad. Acculturative forces are expected to pull second- and third-plus generations towards maladaptive behaviors, but not necessarily the first-generation. The children of immigrants and their offspring are those who often contend with conflicting social expectations, cultural negotiation, and possible rejection of the white mainstream (e.g., education, social conformity) (Portes & Zhou, 1993). As a result, this reality would be expected to produce an “intergenerational severity-based gradient” in which later generations become more susceptible to conflict and maladaptive behaviors not endured in the same way by first-generation immigrants (Vaughn et al., 2014). Alternatively, this could be interpreted as evidence to suggest that the further one is situated from the immigrant designation, the less they are likely to receive the protective benefits of being an immigrant and, in turn, cope with the stressors of becoming more “native.”

As it relates to alcohol use, acculturation processes influence the behaviors used to cope with stressors involved in the immigrant experience. Gil et al. (2000) in their study of Latino youth from South Florida concluded that US-born Latino youth were more likely to engage in higher levels of alcohol use relative to immigrant youth. They also found that how acculturative stress impacts someone varies by an individual’s birth place and by length of time in the US. A similar finding was reported by Bacio et al. (2013) who used data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) to understand how these immigrant categorizations differ on alcohol use outcomes. They found that early drinking initiation and increased alcohol use was more common among those in later generations. Overall, as families acculturate and adapt to US society, traditional values may erode in later generations leaving much of the underlying acculturative stressors to be endured by those with fewer observed immigrant correlates (i.e., the second generation and beyond).

Resting Heart Rate and Alcohol Use

Much of the research examining the effects of RHR on behavior come from scholarship investigating the link between RHR and antisocial behavior or psychopathy (Kavish et al., 2019; Ortiz & Raine, 2004; Portnoy & Farrington, 2015, Portnoy et al., 2020). Yet, the connection between RHR and alcohol use is clear as meta-analytic evidence reports that cardiac health and heart rate variability are associated with a wide range of alcohol abuse disorders (Cheng et al., 2019). Alcohol consumption is believed to suppress autonomic nervous system (ANS) activity and while light drinking does not aggressively impact ANS functionality, increased alcohol use stimulates the HPA-axis and produces stress-related responses in the body (Boschloo et al., 2011; Ralevski et al., 2019). RHR may condition this process and affect alcohol use by potentially decreasing or increasing how stress is processed and ultimately responded to by specific individuals. Individuals with, on average, lower RHR are more likely to report engaging in risky, more stimulating behavior such as drunkenness (Conner‐Warren, 2014; Diseth, 2005; Portnoy & Farrington, 2015; Stone et al., 2018). Conversely, individuals with higher RHR are more likely to consume high amounts of alcohol at different rates as a way to calm their central nervous system despite risks to their health and mortality (Kusuma et al., 2015; Ryu et al., 2014). The literature on examining the influence of RHR on the association between the immigrant experience and alcohol use is extremely limited.

Despite this limited body of research, there are theoretical reasons to hypothesize that RHR at relatively high and low levels may be associated with variability in immigrant response to the acculturation process through alcohol consumption. Since lower RHR is associated with a general increase in behaviors detrimental to one’s physiology and coping capacity, this may color the degree to which an individual concedes to acculturative stress. If acculturative stress is expected to increase the more “native” that someone is, then RHR could augment or depress the resulting behavioral outcomes one may use to cope with such stressors. It is possible then that RHR may operate in a non-linear fashion for immigrants whereby those who score relatively lower are more likely to use alcohol to cope with the stressful experiences associated with the acculturation process, compared to those who have relatively higher levels of RHR. The examination of this research question has the potential to provide essential insight into the immigrant paradox.

Current Study

The current study aims to examine the role of RHR on the association between the immigrant experience and alcohol use and drunkenness in a nationally representative sample of young adults in the US. Specifically, there are two major goals of the current study. First, this study seeks to examine whether and to what extent RHR and the immigrant experience are associated with different forms of alcohol use. Second, the study aims to assess the role of RHR on the associations between the immigrant experience, alcohol use, and drunkenness.

Methods

Data and Sample

The current study used data drawn from The National Longitudinal Study of Adolescent to Adult Health (Add Health). The Add Health is a longitudinal study of a nationally representative sample of US adolescents (Harris et al., 2009). Beginning with the first wave of data collection in 1994 and 1995, the study consists of five waves collecting survey and contextual data from thousands of participants across time. In Wave III, data collection on biological information began which continues into the most current wave.

Specifically, this study analyzed Add Health data from Wave I, Wave III, and Wave IV. Wave I and III were primarily used to collect background characteristics of participants. While Wave III collected biological data, such as urinalysis specimens, Wave IV was the first wave to collect data on cardiovascular functionality among participants (see Entzel et al., 2009). Wave IV was conducted in 2007 to 2008 and included participants from ages 24 to 34. Since a primary variable of the current study addresses RHR, the baseline sample used was the 15,081 participants who provided completed measurements of RHR during data collection. Upon further inspection of the data and using a list-wise deletion procedure, the final analytic sample was N = 4775 respondents.Footnote 1

Measures

Frequency of Alcohol Use

The first outcome of interest was the frequency of alcohol use and represented respondent alcohol use. This was measured using participant survey information from Wave IV, which asked individuals to report how often they drank beer, wine, or liquor during the past 12 months. Participant responses were coded from 0 to 6 using the following response categories: none (= 0), one or two days in the past 12 months (= 1), once a month or less (3 to 12 days in the past 12 months) (= 2), 2 or 3 days a month (= 3), 1 or 2 days a week (= 4), 3 to 5 days a week (= 5), and every day or almost every day (= 6). Table 1 reports the descriptive statistics for this measure. The frequencies for each of these ordinal categories are displayed on Table 2 and shows a general reduction in the number of individuals engaging in alcohol use moving from the first response category to the last.

Table 1 Descriptive statistics
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Table 2 Polychoric correlations
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Drunkenness

The second outcome of interest was drunkenness. This was also measured using participant survey information from Wave IV and asked respondents to report how often they had been drunk during the past 12 months. A similar measure has been used in prior studies to examine drunkenness as an outcome using corresponding data (Niño et al., 2017). Participant response choices were coded 0 to 6 and included none (= 0), one or two days in the past 12 months (= 1), once a month or less (3 to 12 days in the past 12 months) (= 2), 2 or 3 days a month (= 3), 1 or 2 days a week (= 4), 3 to 5 days a week (= 5), and every day or almost every day (= 6). Like the alcohol use variable, less and less of the sample is seen in the more frequent drunkenness categories.

Immigrant Experience

The primary predictor variable was the immigrant experience. This additive measure was generated using three items hypothesized to capture the immigrant experience. The items included having a US-born mother (0 = yes, 1 = no), a US-born father (0 = yes, 1 = no), and being US-born (0 = yes, 1 = no). These items demonstrated high internal consistency (α = 0.831) and were coded as such where higher values reflect higher levels of the immigrant experience.Footnote 2 Each item was added to arrive at the final measurement value ranging from 0 to 3 with a mean value of 0.49. Moreover, immigrant generational dummy measures were created for additional analysis. First-generation refers to a foreign-born individual born to foreign-born parents; second-generation is a US-born individual with at least one foreign-born parent; third-generation is a US-born individual born to two US-born parents.

Resting Heart Rate

Using the cardiovascular measures captured in Wave IV biomarker data, RHR was captured using pulse rate (beats per minute). During in-home interviews, trained and certified interviewers collected the pulse rates of respondents using Microlife blood pressure monitors (MicroLife USA, Inc.; Dunedin, FL). Three serial measurements were taken and captured in 30-second intervals representing three total measurement points; however, the RHR used in this study reflects the average taken between measure 2 and 3 (see Entzel et al., 2009; Kavish et al., 2019). This ranged from 42 to 130 BPM with a mean of 74.06 across the whole sample.

The continuous RHR was used to create categories of respondents with low, mean, and high RHR. With the guidance of prior research on RHR and cardiovascular health, we created these categories relative to respondent sex. As Palatini (1999) noted in their commentary on revising RHR upper and lower limits, female RHR are on average about 3 to 7 BPM greater than males. As such, we grouped individuals into RHR groups based on one standard deviation distance to the mean relative to their respective sex before generating the whole measure. We recognize that an age-adjusted criterion is suitable for generating meaningful RHR categories. Palatini (1999) concluded that heart rate on average decreases at a rate of 1 BPM every 8 years. Considering that we were only able to assess one wave of data with a sample age range of 8 years, however, an age-adjusted RHR measure was not possible. As such, respondents were grouped with the low RHR group if RHR was below one standard deviation below the mean (x̄ = 57.45 BPM; n = 737); mean RHR group if RHR was between one standard deviation below and above the mean (x̄ = 73.61 BPM; n = 3322); and high RHR group if RHR was one standard deviation above the mean (x̄ = 93.28 BPM; n = 716).

Controls

A range of control measures were included in all multivariate analyses. These measures were included to account for factors known to impact RHR and the immigrant experience evidence in the prior literature. Sex was measured dichotomously (1 = male, 2 = female) and age was measured continuously ranging from 25 to 33 years. Additionally, race (0 = non-White, 1 = White) and ethnicity (0 = non-Hispanic, 1 = Hispanic) were examined. Finally, income was assessed. Initially, raw values were used which indicated a mean of $37,839.73 for the sample. However, the distribution of values was heavily skewed. To allow for a more even distribution of income, income was split into quintiles ranging from 1 to 10. The number of individuals in each group ranged from 412 to 572, which used 10% intervals of the income measure to create the groups. The following represents the mean income of each group: (1) $308.83, (2) $6760.21, (3) $15,070, (4) $22,797, (5) $28,662.81, (6) $33,621.24, (7) $38,841.05, (8) $45,974.87, (9) $58,398.11, and (10) $116,616.6.

Analytic Plan

The analyses for the current study focused on (1) calculating polychoric correlations between key variables, (2) estimating a series of negative binomial regression equations to examine the independent effect of the immigrant experience on the frequency of alcohol use and drunkenness, and (3) estimating a simple slopes analysis to examine the role of RHR on the relationship between the immigrant experience and these outcomes. Negative binomial regression models were used because of the count nature of the dependent variables and over-dispersion stemming from outcome values on the left or lower side of distribution. When this occurs, compared to evenly dispersed count data that shows comparable variance and mean estimates, the variance estimate is greater than that of the mean. Alongside application of the Poisson distribution for event counts, this regression type applies the gamma distribution to account for unexplained variance. This is demonstrated by the addition of the parameter K to estimation of the outcome variance, which serves to fit the gamma distribution and right skew of the data (see MacDonald & Lattimore, 2010; Osgood, 2000):

$$E\left(Y\right)=\mu ,\mathrm{ var }\left(Y\right)=\mu +\frac{{\mu }^{2}}{{K}^{-1}}$$

As such, models were estimated for each outcome to examine the association of RHR as a grouping measure, as well as their potential multiplicative interaction effect.

Additionally, we conducted a simple slopes analysis to discern differences between groups of individuals with varying RHR. This was necessary to further investigate the overlapping effects, particularly as they relate to RHR groups. There are several benefits for using a simple slopes analysis to probe for effects across a categorical RHR measure. First, while an interaction model with a continuous variable would be able to assess the multiplicative relationship of an independent variable and moderator on an outcome, it does not assess how RHR groupings significantly differ from one another, especially at the extreme ends of a variable’s distribution. Second, considering the theoretically meaningful cutoffs of RHR and the explorative nature of the current study, a dichotomized/categorized approach helps to examine and present substantive effects, if any, on the aforementioned relationships (see DeCoster et al., 2009). Lastly, simple slopes analyses and significance testing across models simultaneously reduce the threat of type II error and does not increase risk of type I error (Robinson et al., 2013).

Results

Polychoric Correlations

The analysis began by examining the magnitude of the relationship between key variables used in the analysis. Table 2 presents polychoric correlations between all variables. The results revealed that the immigrant experience was negatively correlated with alcohol use frequency (r =  −0.14) and drunkenness (r =  −0.13). RHR was also negatively correlated with alcohol use frequency (r =  −0.09), drunkenness (r =  −0.05), and the immigrant experience (r =  −0.02). Immigrant generation is not reported in these correlations as they highly correlate with immigrant experience, which is consistent considering they are comprised of the same three measures.

Negative Binomial Regression Analyses

A series of negative binomial regression models were estimated where RHR was measured as a grouping variable based on standard deviation distance from the mean. Table 3 presents two separate models: model 1 predicting alcohol use and model 2 predicting alcohol use with the inclusion of an interaction effect between RHR and immigrant experience. Model 1 showed that belonging to both the mean RHR group (b =  −0.082, 95% CI [−0.141, −0.024]) and high RHR group (b =  −0.203, 95% CI [−0.282, −0.125]) relative to the low RHR group was negatively and significantly associated with the frequency of alcohol use. Furthermore, higher levels of the immigrant experience were negatively and significantly associated with alcohol use (b =  −0.069, 95% CI [−0.098, −0.041]). Model 2 demonstrated that a multiplicative interaction between RHR and immigrant experience was not statistically significant.

Table 3 Negative binomial regression models predicting alcohol use frequency (N = 4775)
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Table 4 presents results from negative binomial regression analyses predicting drunkenness. Model 1 showed that only the high RHR group relative to the low RHR group was negatively associated with drunkenness (b =  −0.176, 95% CI [−0.320, −0.032]). This association was not observed between the mean RHR group and drunkenness (b =  −0.088, 95% CI [−0.195, 0.026]). Model 2 here not only showed that the multiplicative interaction was not significant but that the association between high RHR relative to low RHR dropped its significance.

Table 4 Negative binomial regression models predicting drunkenness (N = 4775)
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Simple Slopes Analysis

A simple slopes analysis was conducted to investigate the link between the immigrant experience and alcohol use across RHR groups. Even though the multiplicative interaction terms were non-significant for both outcomes, there still remains the possibility that these findings are masking important and nuanced relationships between the immigrant experience and alcohol use at the tail ends of the distribution, rather than across the entire distribution. To investigate this possibility, negative binomial regressions were estimated to focus on examining these relationships across RHR groupings. Table 5 shows the predicted means of the low, mean, and high RHR groupings across the four possible values for the immigrant experience (0, 1, 2, and 3). For alcohol use frequency, the results revealed a statistically significant difference between the mean and high RHR groups ( χ2 = 24.05, p = 0.002), as well as the low RHR and high RHR groups ( χ2 = 30.41, p = 0.000). Figure 1 provides a visual illustration of these results demonstrating that the greater the immigrant experience, the less likely an individual is to engage in alcohol use. There is, however, a similar, but separate and negative slope between the low RHR group and high RHR group, primarily indicating that high RHR individuals, relative to low RHR individuals, demonstrate an overall reduced likelihood of engaging in alcohol use.

Table 5 Simple slopes analysis predicting alcohol use frequency and drunkenness across low, mean, and high resting heart rate (N = 4775)
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Fig. 1
figure 1

Simple slopes for the effect of immigrant experience on alcohol use frequency by low, mean, and high resting heart rate

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Table 5 also demonstrates results related to drunkenness. The regression coefficient test indicated that there were only significant differences in drunkenness between low RHR and high RHR groups (χ2 = 19.13, p = 0.014). Figure 2 illustrates this association showing that the greater the immigrant experience, the reduced likelihood of engaging in drunkenness. When examining the slopes between low and high RHR groups, there is a clear difference. On the left and negative side of the immigrant experience distribution—the side that is consistent with little to no immigrant experience—low and high RHR are close in values, albeit with high RHR positioned right below low RHR. As the immigrant experience increases, the slopes among groups continue their negative slopes, but the distance widens as immigrant experience increases.

Fig. 2
figure 2

Simple slopes for the effect of immigrant experience on drunkenness by low, mean, and high resting heart rate

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Sensitivity Analyses

While the analysis indicates that the relationship between the immigrant experience and alcohol-related outcomes differ by low and high RHR, further analysis using the more traditional immigrant generational approach is also suitable to ensure that important differences across generational statuses (i.e., first generation, second generation, and third generation) are not lost in the analysis. Table 6 in Appendix A (Supplementary Information) displays three separate models disaggregated by immigrant generation statuses and the influence of RHR on alcohol use. Among second-generation individuals (b =  −0.223, 95% CI [−0.429, −0.016]), only belonging to the high RHR group is significantly associated with increased alcohol use relative to the low RHR group. For the third-generation natives, both belonging to mean RHR (b =  −0.090, 95% CI [−0.156, −0.025]) and high RHR (b =  −0.186, 95% CI [−0.273, −0.099]) increased alcohol use. Similar to Table 6, Table 7 in Appendix A (Supplementary Information) displays three models separated by immigration generation and the influence of RHR on drunkenness. The results suggest that belonging to the mean or high RHR group was not associated with drunkenness. These findings differ compared to the models for alcohol use.

Discussion

The present study examined the role of RHR on the relationship between the immigrant experience, alcohol use, and drunkenness using data from a nationally representative sample. Three major findings emerged. First, we found that the immigrant experience was negatively associated with alcohol use and drunkenness. This finding is consistent with prior literature, which has reported that immigrants are less likely to engage in alcohol misuse (Alamilla et al., 2019; Green & Maggs, 2018). Second, the results revealed that higher RHR was associated with reduced alcohol use and drunkenness. This finding offered evidence to suggest that there is an association between low RHR and higher alcohol use. This would be consistent with sensation-seeking theories, which suggest that individuals seek out behaviors that provide stimulation and arousal (see Kavish et al., 2019; Raine, 2002). For high RHR individuals, however, the dampening effects of alcohol may not yield substantive appeal and reduce the magnitude of alcohol consumption.

Third, our analyses revealed an overlap when considering the connection between the immigrant experience and drinking behaviors by RHR. Specifically, both the immigrant experience and group membership for RHR influenced the degree to which there was an increase or decrease in alcohol use. Regardless of immigrant experience, we found that alcohol use was reduced among those with low RHR, compared to those with high RHR. When we consider the specific differences across the immigrant experience, the higher end of the immigrant experience was associated with reduced alcohol use across low, mean, and high RHR groups, compared to the lower end, and vice versa. In terms of magnitude, for example, Fig. 1 shows a decrease of about 0.2 in alcohol use for a one unit increase in immigrant experience among those with high RHR. This suggests that as one adheres more to the immigrant experience, there is an incremental movement from reporting an average alcohol intake of once a month or less to an average alcohol intake of one or 2 days in the past 12 months (see Table 5).

Results from our sensitivity analysis also provided added nuance as only the third generation demonstrated associations across mean and high RHR groups relative to those with low RHR. This suggests that individuals with a more acculturated, native-born reality are more likely to be influenced by varying levels of RHR when it comes to alcohol use. Potentially, under these circumstances, biological and immigrant indicators may act as protective factors. The same story may not hold when considering drunkenness, however. Even though our simple slopes analysis suggested that RHR was associated with disparate conditions for drunkenness, our findings from the first set of regression analysis and sensitivity analysis demonstrated that there was little to separate the association between RHR and drunkenness when examined across immigrant generations.

In sum, it appears that immigrant indicators provide some resiliency from drinking behaviors as well as RHR, depending on the type of alcohol use behavior. Through an acculturation lens, immigrants do well to have reduced alcohol use and drunkenness behaviors; however, the more native and integrated someone becomes, the less this is the case. Thus, if acculturation operates as a stressful life experience among those with fewer and fewer immigrant indicators (i.e., later generation immigrants or individuals), then drinking alcohol may emerge as a more salient coping mechanism. In the context of RHR, low RHR may play a key role in the acculturation process and dampen the influence of protective structures that immigrants generally benefit from (e.g., culture, familial ties, ethnic enclaves). Despite this, even though RHR does play a role across immigrant indicators and generations, their individual associations on drinking are certainly more pronounced and should also be taken into strong consideration.

This study has limitations that warrant discussion. First, RHR and the outcome measures were only measured at one point in time, which did not allow us to temporally disentangle potential causal effects. However, previous research has reported that resting heart rate tends to be relatively stable across time (see Jennings et al., 2019; Van Hulle et al., 2000). Second, we could not measure heart rate variability (HRV). This is important to future research as HRV allows for a more nuanced view of cardiac health and demonstrates how heart rates respond dynamically to stimuli (Relevski et al., 2019). Second, the immigrant experience was limited to only three indicators. To improve upon this measurement, researchers should attempt to incorporate other factors and dimensions like language, ethnic identity or orientation, and skin color. In an effort to better capture the complexity of this concept known as the immigrant experience, a latent factor or composite measurement approach would be required to adequately capture variation (Sen & Wasow, 2016). In a similar vein, the race and ethnicity measures were limited in their scope in how they distinguished between the two concepts. In relevant situations where researchers choose to rely on available but numerous indicators, they should aim to assess curvilinear or quadratic functional forms to better understand the range of immigrant experiences. In doing so, future studies may better be able to understand these immigrant associations as they relate to other dimensions of alcohol intake including alcohol abuse, prolonged alcohol abuse, and different forms of alcohol use disorders. Additionally, future research should consider other forms of substance use and abuse as well as other coping mechanisms to better understand immigrant adaptations to mainstream US society.

Conclusion

The findings reported in the current study have implications for the biosocial impact of varying RHR levels, the consequences of immigrant realities and nativity, and their potential crossover. With respect to adults, treatments aimed at reducing alcohol use behaviors must consider not just the vulnerabilities marked by clashes between immigrant and native experiences—and the emergent acculturative stress—but how variability in biological functioning account for observed differences across individuals. Prevention efforts made early on in the life-course could offer individuals access and exposure to prosocial coping mechanisms that could help alleviate biological stress in healthy ways. Considering the prominence of low RHR on negative life outcomes (Portnoy & Farrington, 2015), early detection and measurement of RHR would be fruitful in preventative efforts. Identifying how a youth’s RHR is situated relative to their peers early on in the life-course could allow treatment to target the immediate and residual effects of having, on average, low RHR.

Considering the importance of family and traditional values that act as protective factors against antisocial behaviors and heightened alcohol use among immigrants (see Fenimore et al., 2019; Gil et al., 2000), programming efforts should be ethnically sensitive as well as attuned to where someone is situated on the immigrant intergenerational gradient. One example is keepin’ it REAL, which is a program that offers a culturally specific and grounded approach to addressing risk factors among ethnically diverse students in primary and secondary schools (Marsiglia et al., 2010, 2012). These types of programs by design incorporate the acculturation process into curricula to help youth cope with challenges and stressors associated with unique cultural contexts. Consideration for these approaches will allow practitioners and researchers to tailor treatment to specific cross-sections of the immigrant population—as well as the native generations that might benefit more from this type of programming—alongside being able to target risk factors that often lead immigrant, and evident from the results of this study, native youth and children of immigrants to heightened and prolonged antisocial outcomes (e.g., sex, culture, sensation seeking behaviors, for overview of risk factors see Fenimore et al., 2019). In instances where community programming is better able to assess RHR among youth in immigrant-focused and adjacent contexts, tailoring specific efforts can be aimed towards those with potentially heightened risk of antisocial outcomes (i.e., those more native with lower RHR levels relative to peers). Lastly, future research could be better aimed at identifying what protective factors, biological and social, “work” for immigrants as to tailor specific program needs to subsequent generations.

While prior research has found links between immigrant positionality and alcohol-related behaviors, little is known about how RHR and the immigrant experience impact alcohol use behaviors. The results from our analysis showed that RHR and the immigrant experience work independently, and in some instances together, to play roles in alcohol use and drunkenness among immigrants. Overall, the reported findings suggest that immigrant status does not only act as a standalone protective factor against maladaptive behaviors, but also that biological risk and resiliency, as captured by RHR, offer much to understanding how variation in unhealthy alcohol use is related to the immigrant experience.