Association of smoking behavior among Chinese expectant fathers and smoking abstinence after their partner becomes pregnant: a cross-sectional study

We conducted a cross-sectional survey to assess the smoking behavior of Chinese smoking expectant fathers and to explore the factors associated with smoking abstinence after their partner becomes pregnant. We targeted expectant fathers who continued to smoke or who quit smoking after their partner became pregnant. Expectant fathers who accompanied their pregnant partner to a prenatal examination at the obstetrics and gynecology clinic of three tertiary hospitals in China were assessed for eligibility to participate in the study. The selected hospitals in this study have the largest obstetrics and gynecology clinics in the study regions. This study was reported following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE).

Expectant fathers were eligible for this study if they: (1) were aged 18 years or above, (2) smoked at least one cigarette per day for 1 month within the past 12 months, and (3) could read Chinese and communicate in Mandarin. We excluded expectant fathers who were mentally or physically unable to communicate. Those who self-reported as having resumed smoking, or who had an exhaled carbon monoxide level of 4 ppm or above (suggesting smoking within approximately the last 24 h) were identified as current smokers. Those who self-reported as having quit for more than 1 month and whose exhaled carbon monoxide level was less than 4 ppm were identified as ex-smokers.

According to previous literature, 50 of 328 smoking expectant father quit successfully after their partners got pregnant with a quit rate of 15.2% [16]. With a confidence level (CI) of 95% and significance level of 5%, at least 199 participants were needed in this study. The sample size was calculated based on the following formula [17].

A demographic questionnaire was administered to collect participants’ background information, including, age, occupation, family income, education level, number of children, activity level, and alcohol use.

A structured standardized questionnaire (Supplementary) was used in this study, which has been well validated in previous studies [18, 19]. The panel comprised an associate professor, an assistant professor from a local university, and a nurse practitioner in gynecology and obstetrics from a local tertiary hospital, all of whom had extensive knowledge of smoking cessation and obstetrics. In the structured standardized questionnaire, participants’ health-related quality of life was assessed using the 12-Item Short-Form Survey (SF-12) as physical health status (PCS) and mental health status (MCS), respectively. The Chinese version of the SF-12 has been tested and shown to have good internal consistency (0.910) and reliability (0.812) [20]. Participants’ nicotine dependency was assessed with the Fagerström Test of Nicotine Dependence (FTND), the coefficient of construct reliability for the Chinese scale has been empirically examined, with a score of 0.74 [21]. Smoking self-efficacy among expectant fathers was assessed using the Smoking Self-Efficacy Questionnaire (SEQ-12). The interclass correlation coefficients of 0.95 and 0.93 for internal stimuli and external stimuli in the Chinese version were obtained, respectively [22]. Family support was evaluated using the Family Adaptation, Partnership, Growth, Affection, and Resolve (Family APGAR) [23]. The Chinese version of the Family APGAR has demonstrated good test–retest reliability (0.91) [24]. This questionnaire also covers the following areas: (1) whether participants have attended prenatal education and received advice regarding smoking cessation from health care professionals at a clinic, (2) smoking and quitting behaviors before and after the partner became pregnant, (3) intention to quit smoking, (4) knowledge about the health hazards of tobacco use to smokers themselves, pregnant women, fetuses, and newborns, (5) attitude toward tobacco use, (6) and risk perception toward smoking using a binary scale (yes or no).

To identify potential participants at each registration center, promotional posters were placed next to the reception desk, highlighting the nature and purpose of the study. All pregnant women were screened for their husbands’ smoking status. Research nurses then invited smoking expectant fathers to participate in the study, after confirming their eligibility. After receiving an explanation of the study details, expectant fathers were informed that their participation was voluntary and without prejudice to them or their partner. Expectant fathers who agreed to participate were asked to provide their written consent and complete the questionnaire, including demographic information. The entire process required about 30 min and took place while expectant fathers were waiting for their partner to undergo a prenatal examination, causing only minimal disturbance to the clinical routine.

R programming language version 3.1 (The R Project for Statistical Computing, Vienna, Austria) was used to perform all data analyses. Descriptive statistics were used to detail participants’ demographic characteristics and their smoking profile. The frequency and percentage or mean and standard deviation were used to present categorical data and continuous data, respectively.

Lasso regression, a method of feature selection using regularization to minimize prediction error for variables and avoid overfitting, was performed to select variables associated with expectant fathers’ smoking abstinence after their partner became pregnant from all assessed independent variables [25]. The receiver operating characteristic (ROC) curve and Hosmer–Lemeshow test were used to diagnose and evaluate the goodness of fit of the selected model [26, 27]. Multivariable logistic regression using the selected model was then conducted to identify predictors of smoking abstinence in expectant fathers after their partner becomes pregnant.

Using lasso regression, 19 features were selected in the model among 27 independent variables (Fig. 1). The area under the ROC curve (AUC) was 0.913 (Fig. 2) and results of the Hosmer–Lemeshow test (p = 0.154) indicated that the selected model was reliable and acceptable for predicting smoking abstinence among smoking expectant fathers.

Table 5 presents the results of multivariable logistic regression with respect to successful smoking abstinence among expectant fathers after their partner became pregnant. Knowledge about the health hazards of smoking to smokers themselves (odds ratio (OR) 1.39; 95% CI 1.24 to 1.58; p < 0.001), knowledge about the health hazards of SHS to pregnant women (OR 1.46; 95% CI 1.09 to 1.97; p < 0.001) and to the fetus and newborn (OR 1.58; 95% CI 1.25 to 2.03; p < 0.001), and being a first-time expectant father (OR 2.08; 95% CI 1.02 to 3.85; p = 0.046) were found to be significantly positively associated with smoking abstinence among expectant fathers after their partner became pregnant. Severe dysfunctionality in terms of family support (OR 0.48; 95% CI 0.24 to 0.95; p = 0.036) and smoking only outside the home (OR 0.81; 95% CI 0.26 to 0.98; p < 0.001) were found to be significantly negatively associated with expectant fathers’ smoking abstinence after their partner became pregnant.

There were several limitations to this study. First, we relied mainly on self-reported smoking status, which is less desirable than biologically-confirmed smoking status. Second, although we encouraged all pregnant women to invite their smoking husband to participate in this study even if they did not accompany them to a prenatal visit, some expectant fathers were reluctant to join the study. Further study may consider to explore whether male partners who attend prenatal visits are more likely to engage with educational interventions than those who do not. Third, the gestation age of the pregnant women at the time of recruitment varied. As this is a cross-sectional study, some fathers may have relapsed and recommenced smoking after data collection. Researchers may consider conducting a longitudinal study in future to monitor the expectant fathers’ smoking status throughout the gestation period of their partners.

Despite the above limitations, the present findings have important implications for clinical practice and research. Expectant fathers may increase their understanding of their own vulnerability to health risks, emotional responses, and changes in their self-image, which may lead them to be motivated to bring about substantial changes in their health behavior, particularly in terms of taking greater responsibility for their own actions. As the tobacco use rate among expectant fathers in China remains very high, further smoking cessation interventions should be developed, implemented, and evaluated to help this population to quit smoking, especially during the teachable period while their partner is pregnant.

Our results provide useful recommendations for health care professionals in guiding the development of smoking cessation interventions. The findings of this study reveal that knowledge among smoking expectant fathers about the risks of SHS to the health of pregnant women, fetuses, and newborns can serve as powerful motivation for their abstinence from tobacco use. This suggests that educational interventions addressing smoking-related hazards, with a particular focus on maternal and neonatal health, are potentially effective and feasible to motivate smoking expectant fathers to quit smoking.