The Association Between Social Stressors and Home Smoking Rules Among Women With Infants in the United States

Abstract

Objectives. We examined the role of social stressors on home-smoking rules (HSRs) among women with infants in the United States, with attention on the moderating role of smoking status and depression.

Methods. We analyzed data for 118 062 women with recent births in the United States who participated in the Pregnancy Risk Assessment Monitoring System (2004–2010), which is a population-based surveillance data set. We fit multinomial logistic models to predict the odds of partial or no HSRs by a cumulative index of prenatal social stressors.

Results. Compared with those with no stressors, mothers with high levels of social stressors had 2.5 times higher odds of partial or no HSRs. Smokers in the 1–2, 3–5, and ≥ 6 stressor categories were 9.0%, 9.6%, and 10.8% more likely to have partial or no HSRs, respectively. Under the highest levels of stress (≥ 6), nonsmokers were almost as likely as smokers to have partial or no HSRs. In addition, the effects of stress on HSRs were more pronounced for nonsmoker, nondepressed mothers.

Conclusions. Increases in social stressors represented an important risk factor for partial or no HSRs and might have potential negative implications for infants.

The home environment constitutes the most important determinant of infant exposure to secondhand smoke (SHS). SHS is a preventable burden in the US health care system. SHS has pernicious effects on children and infants, with exposure linked to an increased risk of acute respiratory infection, ear infections, asthma, and sudden infant death syndrome.^1,2 Although information regarding the dangers of SHS is widespread and generally acknowledged by all sociodemographic groups within the United States, individuals continue to smoke or allow smoking in their households, putting their health and their children’s health at risk. Home smoking rules (HSRs), which limit the amount of smoking allowed in the home, are generally acknowledged as an effective way to minimize SHS, but little is known about how social stressors affect HSRs in households with infants.

Mounting societal pressures have led to restrictions in public smoking as a means to limit exposure to SHS in common areas.^3,4 Similarly, individual HSRs, partial (smoking disallowed in designated areas of the home) and full (smoking disallowed anywhere in the home), have increasingly been used to limit SHS exposure in the home.^5–7 However, SHS exposure remains a significant public health concern. Although little information is available on SHS for infants, approximately 50% of children aged 3 to 11 years were exposed to secondhand smoking in 2005 to 2008.⁸ National health objectives in Healthy People 2020 aim to reduce childhood exposure to SHS and to increase the proportion of smoke-free homes from 69.1% in 2006 to 2007 to 87% by the year 2020.⁸ The prevalence of HSRs varies by sociodemographic characteristics and within subpopulations.^9,10 For example, Gibbs et al.¹⁰ showed that although an overwhelming majority of homes with infants have complete HSRs, the prevalence varies by state, education level, and race/ethnicity; lower socioeconomic status and racial/ethnic minority groups are more likely to have partial or no HSRs.

High levels of social stress may impede the practice of HSRs. Social stress may have an independent relationship with HSRs through the loss of social control, self-efficacy, or power within a household context. Individuals facing compromised resources are likely to have fewer options to cope with stress and may have diminished control over enforcing health-promoting norms.¹¹ They may also have lower levels of social support or external locus of control within their environment.¹² HSRs are less likely among former or current smokers, regardless of socioeconomic status.^9,10 Smoking, a health compromising behavior, may be a coping mechanism in resource-limited social or environmental settings, and stress may trigger the need for smoking among current or previous smokers.^13–15 Stressors may precipitate postpartum depressive symptoms, reducing HSRs through intrapersonal characteristics of self-determination or self-efficacy, thereby moderating the relationship between stressors and HSRs. Maternal depression has been consistently associated with negative child-rearing behaviors.^16,17 In addition, depression may indirectly be negatively associated with HSRs because of the higher prevalence of smoking behavior^18,19 or the lower likelihood of smoking cessation among depressed people.²⁰

We aimed to explore the relationship between prebirth stressors and postpartum HSRs in a population-based sample of women with infants in the United States. We present 2 primary hypotheses: (1) cumulative stressors are associated with a lower likelihood of HSRs among recent mothers, controlling for smoking status and depression; and (2) current smoking will moderate the relationship between stress and HSRs; stress will have a stronger negative association with HSRs among current smokers, and the moderating effect of smoking status will be stronger for those who are not depressed.

METHODS

The Pregnancy Risk Assessment Monitoring System (PRAMS) provided data from 2004 to 2010. PRAMS is a population-based, cross-sectional, self-reported surveillance system of maternal behaviors conducted through state health departments and is overseen by the Centers for Disease Control and Prevention.²¹ Respondents in participating states were randomly selected based on birth certificate records, with questionnaires mailed to them postpartum. Additional efforts were made through telephone follow-up to ensure response rates of at least 65% and to minimize recall bias. Survey responses took place an average of 116 days postpartum (range = 57–307 days), with 90% of survey responses occurring within 162 days of birth. Ancillary analysis showed that time of response or age of the infant did not influence results. Survey data were linked to birth certificate data and weighted to be more representative of all women delivering live births in each participating state. Participation in the PRAMS surveillance and the administration of specific survey questions were determined by each individual state. Although 40 states currently participate in PRAMS, representing 78% of all live births in the United States,²¹ we were limited to 29 states that chose to ask questions about HSRs during the study period. The 29 states included in this analysis were Alaska, Arkansas, Colorado, Delaware, Georgia, Hawaii, Illinois, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, Nebraska, New Jersey, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas, Utah, Washington, Wisconsin, West Virginia, and Wyoming. We included a total of 118 062 women with infants in this study after excluding 1771 respondents with missing HSR information. All data included appropriate sample weights and were adjusted from the complex PRAMS survey design.²²

An HSR was the dependent variable and was ascertained from the question, “Which of the following statements best describes the rules about smoking inside your home now?” Responses included “no one was allowed to smoke anywhere inside my home” (complete restriction), “smoking was allowed in some rooms at some times” (partial restriction), or “smoking was permitted anywhere inside my home” (no rules). We dichotomously classified HSRs as either complete rules (0) or partial and no rules (1).

Variables

Stress variables were the mother’s self-reported stressful life events from the Modified Life Event inventories. They included affirmative responses to 13 items of stressful experiences in the 12 months before the child’s birth, including the following: a close family member was sick and had to go to the hospital, recent separation or divorce, moved to a new address, homeless, partner or husband lost a job, lost a job, argued with partner more than usual, partner stated they did not want pregnancy, a lot of bills that could not be paid, in a physical fight, jail for mother or partner, someone very close had bad problem with drinking or drugs, and death of someone close. Stress variables were categorized into 0, 1 to 2, 3 to 5, and 6 or more, following the PRAMS coding convention.

Depression was derived from the sum of response scores (on a Likert scale of 1 = never, 2 = rarely, 3 = sometimes, 4 = often, 5 = always) to 3 questions about how often the respondent felt “down, depressed, or sad,” “hopeless,” or “slowed-down” since their new baby was born. The cumulative depressive symptoms score ranged from 3 to 15, and depression was coded dichotomously as 0 if 9 or less, and coded as 1 if the sum measure was greater than 9.²³

Sociodemographic characteristic variables included mothers’ age (< 20, 20–34, and ≥ 35 years), race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, and other race), and marital status (married or not currently married). Other variables included previous children, a dichotomous variable indicating whether the mother had any previous live births, and smoking status, because these factors were shown to be independently associated with the adoption of complete HSR.^24–27 Postpartum smoking behavior was categorized as never smoker, former smoker, or current smoker. Socioeconomic characteristic variables included education and household income. Education was defined as the highest level of completed education and categorized as less than high school, high school, some college, or college degree. Household income was categorized as less than $10 000, $10 000–$19 999, $20 000–$34 999, $35 000–$49 999, and $50 000 or more.

Analyses

First, all variables were categorical, and their frequencies, disaggregated by stress, were compared by χ² analysis in Table 1. Second, we examined the association between stress and HSRs with multivariable logistic regression analyses in Table 2. Model 1 presented a baseline model by regressing partial or no HSRs on stressors, controlling for sociodemographic and socioeconomic variables. Model 2 included model 1 and smoking status. Model 3 included the interaction between current smoking and stress categories. Third, we focused on the relationship between stressors and HSRs by depression status in Table 3. Model 1 included stressors and smoking status, whereas model 2 added the interactions between smoking status and stressors. Results are presented as odds ratios (ORs; exponentiated coefficients) and 95% confidence intervals (CIs).

TABLE 1—

Comparison of Distributions of Women With Recent Births by Home Smoking Rules: Pregnancy Risk Assessment Monitoring System, United States, 2004–2010

		Home Smoking Rules		Significancea
Characteristic	Overall	Full	Partial/None	χ2	P
Smoking rules
Full	0.94	. . .	. . .		. . .
Partial/none	0.06	. . .	. . .
Number of stressors				319.15	< .002
0	0.29	0.30	0.12
1–2	0.42	0.42	0.34
3–5	0.23	0.23	0.38
≥ 6	0.06	0.05	0.16
Smoking status
Never smoker	0.76	0.78	0.43	955.31	< .001
Former smoker	0.07	0.07	0.07
Current smoker	0.17	0.14	0.50	169.51	< .001
Depression	0.11	0.06	0.13
Age categories, y				241.39	< .001
< 20	0.10	0.09	0.22
20–34	0.76	0.76	0.71
≥ 35	0.14	0.15	0.07
Race/ethnicity				152.69	< .001
Non-Hispanic White	0.60	0.60	0.59
Non-Hispanic Black	0.13	0.12	0.26
Hispanic	0.21	0.22	0.11
Other	0.07	0.07	0.04
Marital status				1110.47	< .001
Not married	0.38	0.36	0.71
Married	0.62	0.64	0.29
Previous children				5.27	< .022
0	0.41	0.41	0.43
≥ 1	0.59	0.59	0.57
Education				276.90	< .001
< high school	0.18	0.17	0.31
High school	0.28	0.27	0.41
Some college	0.25	0.25	0.20
College	0.30	0.31	0.07
Income, $				262.01	< .001
< 10 000	0.19	0.18	0.41
10 000–19 999	0.15	0.15	0.22
20 000–34 999	0.16	0.16	0.17
35 000–49 999	0.10	0.10	0.05
≥ 50 000	0.40	0.42	0.15
Sample size	118 062	110 979	7083

Note. Analysis includes sample weights and adjustment for complex sample design.

^aStatisical signifance of adjusted Pearson χ².

TABLE 2—

Logistic Regression Analysis of Partial/No Home Smoking Rules Among Women With Recent Births, Pregnancy Risk Assessment Monitoring System, United States, 2004–2010

Variable	Model 1, OR (95% CI)	Model 2, OR (95% CI)	Model 3, OR (95% CI)
Number of stressors (Ref: 0)
1–2	1.63 (1.4, 1.89)	1.51 (1.3, 1.76)	1.54 (1.28, 1.86)
3–5	2.30 (1.98, 2.68)	1.91 (1.64, 2.23)	2.13 (1.75, 2.59)
≥ 6	3.35 (2.81, 3.99)	2.50 (2.08, 3.00)	3.07 (2.37, 3.97)
Smoking status (Ref: never smoker)
Former smoker		1.17 (0.97, 1.43)	1.15 (0.94, 1.40)
Current smoker		3.11 (2.77, 3.49)	3.85 (2.89, 5.11)
Interactions (Ref: 0)
Current smoker × stressors (1–2)			0.90 (0.65, 1.25)
Current smoker × stressors (3–5)			0.74 (0.54, 1.03)
Current smoker × stressors (≥ 6)			0.64 (0.44, 0.94)
Sociodemographic and socioeconomic controls
Age categories, y (Ref: 20–34)
< 20	1.34 (1.16, 1.54)	1.47 (1.28, 1.70)	1.47 (1.28, 1.70)
≥ 35	0.91 (0.77, 1.07)	0.94 (0.8, 1.11)	0.94 (0.8, 1.11)
Race/ethnicity (Ref: Non-Hispanic White)
Non-Hispanic Black	1.23 (1.1, 1.37)	1.63 (1.45, 1.83)	1.63 (1.45, 1.83)
Hispanic	0.26 (0.21, 0.32)	0.41 (0.33, 0.50)	0.41 (0.33, 0.50)
Other	0.75 (0.61, 0.91)	0.88 (0.72, 1.07)	0.89 (0.73, 1.08)
Not married (Ref: married)	1.82 (1.62, 2.06)	1.57 (1.39, 1.77)	1.55 (1.38, 1.75)
≥ 1 previous children (Ref: 0)	1.15 (1.04, 1.27)	1.09 (0.98, 1.21)	1.09 (0.98, 1.21)
Education (Ref: high school)
< high school	1.31 (1.16, 1.48)	1.23 (1.09, 1.40)	1.24 (1.09, 1.40)
Some college	0.64 (0.56, 0.72)	0.70 (0.62, 0.80)	0.70 (0.62, 0.80)
College	0.36 (0.3, 0.44)	0.47 (0.38, 0.57)	0.47 (0.39, 0.58)
Income, $ (Ref: ≤ 10 000)
10 000–19 999	0.87 (0.76, 0.99)	0.89 (0.78, 1.02)	0.89 (0.78, 1.02)
20 000–34 999	0.78 (0.67, 0.91)	0.83 (0.72, 0.97)	0.83 (0.71, 0.97)
35 000–49 999	0.51 (0.41, 0.63)	0.57 (0.46, 0.70)	0.57 (0.45, 0.70)
≥ 50 000	0.46 (0.39, 0.54)	0.51 (0.44, 0.61)	0.52 (0.44, 0.61)
Constant	0.05 (0.04, 0.06)	0.04 (0.03, 0.04)	0.03 (0.03, 0.04)

Note. CI = confidence interval. Analysis includes sample weights and adjusts for complex sample design. The sample size was n = 105 512.

TABLE 3—

Logistic Regression Analysis of Home Smoking Rules on Stressors and Smoking by Depression Status Among Women With Recent Births: Pregnancy Risk Assessment Monitoring System, United States, 2004–2010

Variable	Model 1, OR (95% CI)	Model 2, OR (95% CI)
Nondepressed (n = 55 748)
Number of stressors (Ref: 0)
1–2	1.73*** (1.40, 2.15)	1.85*** (1.42, 2.40)
3–5	2.14*** (1.71, 2.69)	2.55*** (1.93, 3.38)
≥ 6	2.65*** (2.00, 3.50)	3.78*** (2.62, 5.46)
Smoking status (Ref: never smoker)
Former smoker	1.05 (0.80, 1.37)	1.01 (0.77, 1.32)
Current smoker	2.76*** (2.32, 3.27)	4.17*** (2.75, 6.34)
Interactions (Ref: 0)
Current smoker × stressors (1–2)		0.75 (0.47, 1.21)
Current smoker × stressors (3–5)		0.58* (0.36, 0.93)
Current smoker × stressors (≥ 6)		0.43** (0.25, 0.75)
Depressed (n = 8,059)
Number of stressors (Ref: 0)
1–2	1.70 (0.90, 3.19)	1.10 (0.52, 2.34)
3–5	1.85* (1.01, 3.39)	1.31 (0.63, 2.71)
≥ 6	2.55*** (1.36, 4.76)	1.82 (0.82, 4.07)
Smoking status (Ref: never smoker)
Former smoker	1.93** (1.18, 3.14)	1.93** (1.19, 3.13)
Current smoker	3.30*** (2.36, 4.61)	1.42 (0.48, 4.18)
Interactions (Ref: 0)		2.87 (0.85, 9.64)
Current smoker × stressors (1–2)
Current smoker × stressors (3–5)		2.36 (0.74, 7.53)
Current smoker × stressors (≥ 6)		2.32 (0.69, 7.80)

Note. CI = confidence interval. Analysis includes sample weights and adjusts for complex sample design. All models control for age, race, marital status, previous births, education, and income.

*P ≤ .05; **P ≤ .01; ***P ≤ .001.

RESULTS

The descriptive statistics, including the prevalence of HSRs by demographic and socioeconomic variables, are shown in Table 1. Overall, 94% of the sample had full HSRs. Respondents who indicated higher levels of stress were more likely to have partial or no HSRs. For example, 16% of the partial or no HSR group indicated 6 or more stressors, compared with 5% of the full HSR group. Eleven percent of the sample had scores that suggested postpartum depression, with a statistically significant proportion of depressed mothers indicating higher partial or no HSRs (13% vs 6%; P ≤ .001). Current smokers included a large proportion of the partial or no HSR group (50% compared with 17% of the general sample). The adjusted Pearson χ² significance test also indicated that women with partial or no HSRs were more likely to be younger, non-Hispanic Black, unmarried, first-time mothers, less educated, and have lower income.

In Table 2, model 1 showed that stressors appeared to have an independent association with HSRs, after controlling for sociodemographic and socioeconomic characteristics. Each level of reported stressors was associated with higher odds of partial or no HSRs, compared with absence of stressors (referent category). For example, those with 6 or more stressors had an OR of 3.35 (95% CI = 2.81, 3.99), compared with 2.30 (95% CI = 1.98, 2.68) among those with 3 to 5 stressors and 1.63 (95% CI = 1.40, 1.89) among those with 1 to 2 stressors. Comparing the 1 to 2 stressor category to the 3 to 5 stressor model increased the odds of partial or no HSRs by 41% ([ln 2.30-ln 1.63]/[ln 2.30]) × 100 whereas the 3 to 5 stressors to the 6 or more stressors category increased the odds of partial or no HSR by 31%. Model 2 indicated that current smokers were more likely than nonsmokers to have partial or no HSRs (OR = 3.11; 95% CI = 2.77, 3.49), and that smoking reduced the effect size in the relationship between stress levels and HSRs when introduced into the model.

Model 3 included the interaction terms for current smokers and stress levels. Mean predicted probabilities were calculated for each individual based on their sociodemographic, smoking, and stress characteristics. Figure 1 illustrates these probabilities and shows that the probability of partial or no HSRs generally increased with the number of stressors for both smokers and nonsmokers. The increase was more rapid at lower numbers of stressors. Marginal effects (the unit increase in the probability of partial or no HSRs for a change in an indicator variable from 0 to 1) from model 3 indicated that much of this increase in the probability of partial or no HSRs was captured in other sociodemographic variables. Being a smoker increased the probability of partial or no HSRs by 7.2% points, an increase of more than 100% from the baseline rate of 6% (Table 1). Smokers with 1 to 2, 3 to 5, and 6 or more stressors were 9.0%, 9.6%, and 10.8% more likely to have partial or no HSRs, respectively. Interaction terms were included for these calculations. Although not all interactions were independently statistically significant at traditional levels, all interactions were jointly significant with the main terms. Nonsmokers with 1 to 2, 3 to 5, and 6 or more stressors were 2.3%, 4.0%, and 6.0% more likely to have partial or no HSRs, respectively.

FIGURE 1—

Probability of partial or no home smoking rules by stressors and smoking status for women with recent births: Pregnancy Risk Assessment Monitoring System, United States 2004–2010.

Table 3 shows the results disaggregated by depression status. Model 1 (“Nondepression”) shows that the stressors remained independently associated with partial or no HSRs for nondepressed mothers, at slightly higher odds than those found in the overall sample (see Table 2, model 2). Model 2 included the interaction terms for current smoking and stressors, and presented coefficients that were larger in magnitude and in significance compared with the overall sample. For example, the OR for the current smoker by high stressor (≥ 6) category was 0.43 (95% CI = 0.25, 0.75) for nondepressed individuals, compared with an OR of 0.64 (95% CI = 0.44, 0.94) in the full model. Table 3 (“Depression”) shows the same models for those with depressive symptoms. The results showed a similar relationship between stressors and partial or no HSRs, albeit with less precision. Among those with depression, former smoker (OR = 1.93; 95% CI = 1.18, 3.14) and current smoking status (OR = 3.30; 95% CI = 2.36, 4.61) were associated with higher odds of partial or no HSRs compared with nondepressed former (OR = 1.05; 95% CI = 0.80, 1.37) and current smokers (OR = 2.76; 95% CI = 2.32, 3.27), respectively. The interaction between current smoker and stressors was not statistically significant in the nondepressed subsample.

Focusing on the nondepressed respondents, marginal effects for model 2 indicated that smokers were 7.2% (136% of the baseline rate of 5.5% for nondepressed respondents) more likely to have partial or no HSRs. Marginal effects for smokers were similar to those estimated from Table 2, model 3. Smokers with 1 to 2, 3 to 5, and 6 or more stressors were 8.6%, 9.6%, and 10.0% more likely to have partial or no HSRs, respectively. Results for nondepressed nonsmokers were more striking. Nonsmokers with 1 to 2, 3 to 5, and 6 or more stressors were 3.2%, 4.9%, and 6.9% more likely to have partial or no HSRs, respectively. The estimated marginal effects were larger than those for the full sample (i.e., the partial or no HSR baseline rate was lower than 5.5%). For the full sample (Table 2, model 3), nonsmokers with 1 to 2 stressors were 89% more likely to have partial or no HSRs, and those with 6 or more stressors were 100% more likely to have partial or no HSRs. For nondepressed respondents, having 3 to 5 stressors increased the probability of partial or no HSRs by 89% and having 6 or more stressors increased the probability by 125%.

DISCUSSION

Our study of recent mothers showed that stress was a key factor for incomplete or absent HSRs. It also showed that the impact of stressors might have been modified by a woman’s smoking and depression status. Increasing numbers of social stressors were associated with a higher risk of partial or no HSRs, and a woman’s smoking status moderated the relationship between stress and partial or no HSRs. These results highlighted the importance of prepregnancy stress-related processes for their role in HSRs for mothers and their infants, who are a particularly vulnerable group at risk for SHS effects. It was somewhat reassuring that this cohort of new mothers had a high level of complete HSRs (94% compared with 79.1%) in the general US population.⁸ Similar to other studies, we found that race/ethnicity, income, and education were each important factors in HSRs, with social disadvantages generally associated with higher risk of partial or no HSRs. Hispanics were an exception to this group, and further exploration of the factors that explain high levels of HSRs among Hispanics warrants further exploration.

Social stress might constitute a potential pathway for the lack of HSRs through 3 potential and interrelated mechanisms. First, social stress might have an independent relationship with HSRs through the loss of social control, self-efficacy, or power within a household context. For instance, a younger unmarried expectant mother living with her parent(s) or family might be powerless to change established and immutable smoking rules. Also, individuals faced with continuous stressors and broader structural constraints (e.g., poverty, limited neighborhood resources) might have fewer resources and little control over health behaviors and health-related rules around them.¹¹ Increased levels of stress might also indicate lower levels of social support or external locus of control within one’s environment.¹²

Second, smoking, a health compromising behavior, might be a coping mechanism in resource-limited social or environmental settings. Psychosocial stressors, including both acute life events and chronic stressors, have been consistently implicated in tobacco initiation and use. Consequently, a vicious cycle develops in which smoking may serve to cope with stress, and stress may trigger the need for smoking among current or previous smokers.^13–15 HSRs are affected by current smoking status of adult household members. We showed that current smokers were less likely to have complete HSRs than former smokers or nonsmokers, regardless of socioeconomic status, which supported the results from other studies.^9,10 Stress might therefore indirectly limit HSR rates through increased smoking prevalence and have a stronger impact on HSRs for current smokers.

In our study, former and current smokers had higher odds of partial or no HSRs, suggesting that smoking might moderate the relationship between stressors and HSRs, which was consistent with research that linked stressors to negative health behaviors.^28–30 The predicted probability of partial or no HSR among smokers increased with their numbers of stressors. We observed a similar but less striking effect among nonsmokers. At the highest levels of stressors, nonsmokers and smokers were almost equally as likely to have partial or no HSRs. Stress might discourage smoking rules because of increased rates of coping-related tobacco use, because stress has been linked to increased rate of smoking.¹⁴ Alternatively, increasing levels of stress might promote smoking in the household because of a diminished capacity for nonsmoking mothers to control their home environment.

Third, exposure to stressors might be associated with heightened levels of mental distress or depression, which might exacerbate feelings of helplessness, pessimism, or fatalism. Stressors might precipitate postpartum depressive symptoms, reducing HSRs through intrapersonal characteristics of self-determination or self-efficacy, and thereby, moderating the relationship between stressors and HSRs. Others showed that maternal depression was associated with negative child-related behaviors. Compared with mothers without depression, depressed mothers had reduced sensitivity to their child’s needs, lower child responsiveness, and fewer preventive health practices.^16,17 In addition, depression might indirectly be negatively associated with HSRs because of the higher prevalence of smoking behavior^18,19 or the lower likelihood of smoking cessation.²⁰ We found that depression weakened the relationship among stress, smoking, and HSRs. For nondepressed mothers, the effects of stress were great, particularly for nonsmokers. Having 3 to 5 stressors increased the probability of partial or no HSRs by 89% for nonsmokers and by 38% for smokers. This observation might be consistent with the observation that smoking might be a coping behavior for stress.

Limitations

Our study had some limitations that warrant mention. The survey was both cross-sectional and self-reported; therefore, we could not reach any causal conclusions. Although parental report of home rules were linked to objective markers of SHS in other studies,³¹ it was also quite possible that self-reported full HSRs were overreported, which was consistent with previously reported social desirability of nonsmoking status.

We lacked detailed information about either partner or family smoking status and information about family dynamics pertaining to household decision-making.³² We were unable to determine the household structure of the new mother. For instance, it was highly likely that a younger mother (who had a higher likelihood of partial or no HSRs) might not be the head of the household, might live with relatives, and might have had less control over the household rules. This suggested the potential for future research on household power differentials and household member smoking concordance with HSRs; these are arrangements that are likely shaped by the key social factors of age, income, and education. For instance, we found that although domestic abuse before pregnancy had a slight positive relationship with partial or no HSRs (results not shown), the relationship was minimized with the inclusion of social stressors. Additional exploration into the unique contributions of both prenatal and postpartum specific stressors to HSRs could further explain the importance of household dynamics by understanding the relative importance of specific relationship, financial, or emotional stressors. Although we were limited to an examination of prenatal stressors, this was a crucial time for potential health interventions. Identifying prenatal stressors could assist obstetric and infant care providers in identifying high-risk groups for more focused and proactive implementation of HSRs before or shortly after the infant’s birth.

Future studies would also benefit from more specific information pertaining to the cultural–environmental context of values or attitudes, the social context of home smoking norms, and the built environment. For instance, window placement, yard and porch availability, square footage, and safety concerns about open windows or smoking outdoors at night were likely to be related to both stressors and HSRs.^33,34

Our results suggested that prenatal stress-related factors were associated with HSRs, which are a public health concern for children’s development. Restriction of home smoking has both short- and long-term benefits. However, an estimated 35% to 50% of US children are regularly exposed to household SHS.^8,32 A push to institute HSRs might decrease both adult and child exposure to SHS and might reduce future adolescent smoking. Households with strict HSRs might also give family members a useful strategy to discourage or reduce tobacco use for current household smokers.

Stressors were associated with higher levels of smoking and a higher risk of postpartum depression, both of which were related to HSRs and maintained an independent relationship with partial or no HSRs. This indicated the public relevance of addressing the negative consequence of social stressors on SHS in households with young children. The independent relationship between prepregnancy stressors and postpartum HSRs might be indicative of negative psychosocial impacts on self-efficacy, locus of control, or helplessness.¹² This relationship might also reflect larger social structural factors pertaining to socioeconomic disadvantage (e.g., neighborhood conditions, job opportunities) or racial/ethnic discrimination that both increase stressor risk and limit health-promoting opportunities.¹¹

Conclusions

Pregnancy and recent birth are key intervention time points for parents to change their smoking behaviors.³¹ Although a large percentage of women with infants in our study reported complete HSRs, public health efforts are still needed to limit in-home smoking and SHS exposure for children.⁸ Our findings highlighted the importance of social stressors and suggested that mitigation of social stressors in future studies might be an important avenue to reduce the risk of SHS among infants. This suggested that stress reduction, effective stress management techniques, negotiation skills, and assertiveness training should be targeted toward mothers with little household power. Interventions targeting all household members should be a high priority for future studies on the mitigation of the association of partial or no HSRs and stressors, particularly for individuals with a heightened risk of partial or no HSRs (i.e., lower education, non-Hispanic Black, younger). Although a combination of smoking cessation, mental health screening, and stress management intervention would appear most prudent, future research would benefit from a focus on how stress reduction strategies might be beneficial in lieu of low efficacy smoking cessation programs or insufficient mental health treatment opportunities.