Alcohol, Tobacco and Caffeine Use: Spouse Similarity Processes

The impact of assortative mating, participation bias and socioeconomic status on the polygenic risk of behavioural and psychiatric traits

To investigate assortative mating (AM), participation bias and socioeconomic status (SES) with respect to the genetics of behavioural and psychiatric traits, we estimated AM signatures using gametic phase disequilibrium and within-spouses and within-siblings polygenic risk score correlation analyses, also performing a SES conditional analysis. The cross-method meta-analysis identified AM genetic signatures for multiple alcohol-related phenotypes, bipolar disorder, major depressive disorder, schizophrenia and Tourette syndrome. Here, after SES conditioning, we observed changes in the AM genetic signatures for maximum habitual alcohol intake, frequency of drinking alcohol and Tourette syndrome. We also observed significant gametic phase disequilibrium differences between UK Biobank mental health questionnaire responders versus non-responders for major depressive disorder and alcohol use disorder. These results highlight the impact of AM, participation bias and SES on the polygenic risk of behavioural and psychiatric traits, particularly in alcohol-related traits.

The mechanism of assortative mating for educational attainment: a study of Finnish and Dutch twins and their spouses

Introduction: Assortative mating refers describes a phenomenon in which individuals with similar phenotypic traits are more likely to mate and reproduce with each other; i.e. assortative mating occurs when individuals choose partners based on their similarity or dissimilarity in certain traits.to patterns of non-random mating of spouses leading to phenotypic resemblance. There are various theories about the its underlying mechanisms, which have different genetic consequences. Methods: We analyzed examined two possible mechanisms underlying assortative mating - phenotypic assortment and social homogamy - for educational attainment in two countries utilizing data of mono- and dizygotic twins and their spouses (1,451 Finnish and 1,616 Dutch twin-spouse pairs). Results: The spousal correlations were 0.51 in Finland and 0.45 in the Netherlands, to which phenotypic assortment contributed 0.35 and 0.30, and social homogamy 0.16 and 0.15, respectively. Conclusion: Both social homogamy and phenotypic assortment are important processes in spouse selection in Finland and the Netherlands. In both countries, phenotypic assortment contributes to a greater degree to the similarity of spouses than social homogamy.

The impact of spousal behavior changes on smoking, drinking and physical activity: The longitudinal survey of middle-aged and elderly persons in Japan

The purpose of this study is to assess how one spouse's behavior change can influence their partner's successful behavior changes in smoking, drinking and physical activity. We used data from 10-wave prospective annual surveys of 9417 married couples (discrete-time person-years = 118,876) aged 50-59 years in the Longitudinal Survey of Middle-aged and Elderly Persons in Japan. A logistic generalized estimating equation model with discrete-time design was used among individuals who smoked at baseline to examine the impact of their spouse's health behaviors (i.e. quit smoking, stable non-smoker, or started smoking in reference to stable smoker) on changes in their own behavior (quitting smoking) which lasted one year or more. Similarly, reducing alcohol intake and starting physical activity were individually analyzed. Partners of spouses who had quit smoking had higher odds of quitting smoking themselves than partners of spouses who were stable smokers. The multivariable odds ratios[95%CI] in men and women were 1.94[1.23-3.07] and 2.89[1.81-4.52]. An association was found in partners of spouses who had been stable non-smokers (OR:1.64[1.33-2.03] and 2.20[1.66-2.94]), but not after spouses had started smoking (OR:1.29[0.71-2.36] and 1.27[0.54-2.99]). Similar associations were found for reducing alcohol intake and starting physical activity although for physical activity, the association was still found after the spouse had become physically inactive. Couples affect each other's health behaviors. Both male and female participants had higher odds of adopting positive health behavior changes if these changes had previously been made by their spouse.

Similarities in cardiometabolic risk factors among random male-female pairs: a large observational study in Japan

Background:

Previous observational studies have shown similarities in cardiometabolic risk factors between spouses. It is still possible that this result reflects the age similarity of spouses rather than environmental factors of spouses (e.g. cohabitation effect). To clarify the importance of mate cardiometabolic risk factors for similarity of environmental factors, it is necessary to examine whether they are observed in random male-female pairs while maintaining the age of the spousal pairs. This study aimed to determine whether the similarities found between spousal pairs for cardiometabolic risks were also observed between random male-female pairs.

Methods:

This cross-sectional study included 5,391 spouse pairs from Japan; data were obtained from a large biobank study. For pairings, women of the same age were randomly shuffled to create new male-female pairs of the same age as that of the original spouse pairs. Similarities in cardiometabolic risk factors between the random male-female pairs were analysed using Pearson’s correlation or age-adjusted logistic regression analyses.

Results:

The mean ages of the men and women were 63.2 and 60.4 years, respectively. Almost all cardiometabolic risk factors similarities were not noted in cardiometabolic risk factors, including the continuous risk factors (anthropometric traits, blood pressure, glycated haemoglobin level, and lipid traits); lifestyle habits (smoking, drinking, and physical activity); or diseases (hypertension, type 2 diabetes mellitus, and metabolic syndrome) between the random male-female pairs. The age-adjusted correlation coefficients ranged from − 0.007 for body mass index to 0.071 for total cholesterol. The age-adjusted odds ratio (95% confidence interval) for current drinkers was 0.94 (0.81 − 1.09); hypertension, 1.07 (0.93 − 1.23); and type 2 diabetes mellitus, 1.08 (0.77 − 1.50).

Conclusion:

In this study, few similarities in cardiometabolic risk factors were noted among the random male-female pairs. As spouse pairs may share environmental factors, intervention strategies targeting lifestyle habits and preventing lifestyle-related diseases may be effective.

Spousal Concordance and Cross-Disorder Concordance of Mental Disorders: A Nationwide Cohort Study

OBJECTIVE

Although both partners of a married couple can have mental disorders, the concordant and cross-concordant categories of disorders in couples remain unclear. Using national psychiatric population-based data only from patients with mental disorders, we examined married couples with mental disorders to examine spousal concordance and cross-disorder concordance across the full spectrum of mental disorders.

METHODS

Data from the 1997 to 2012 Taiwan Psychiatric Inpatient Medical Claims data set were used and a total of 662 married couples were obtained. Concordance of mental disorders was determined if both spouses were diagnosed with mental disorder of an identical category in the International Classification of Diseases, Ninth Revision, Clinical Modification; otherwise, cross-concordance was reported.

RESULTS

According to Cohen's kappa coefficient, the most concordant mental disorder in couples was substance use disorder, followed by bipolar disorder. Depressive and anxiety disorders were the most common cross-concordant mental disorders, followed by bipolar disorder. The prevalence of the spousal concordance of mental disorders differed by monthly income and the couple's age disparity.

CONCLUSION

Evidence of spousal concordance and cross-concordance for mental disorders may highlight the necessity of understanding the social context of marriage in the etiology of mental illness. Identifying the risk factors from a common environment attributable to mental disorders may enhance public health strategies to prevent and improve chronic mental illness of married couples.

Spousal associations of serum metabolomic profiles by nuclear magnetic resonance spectroscopy

Phenotype-based assortative mating is well established in humans, with the potential for further convergence through a shared environment. To assess the correlation within infertile couples of physical, social, and behavioural characteristics and 155 circulating metabolic measures. Cross sectional study at a tertiary medical center of 326 couples undertaking IVF. Serum lipids, lipoprotein subclasses, and low-molecular weight metabolites as quantified by NMR spectroscopy (155 metabolic measures). Multivariable and quantile regression correlations within couples of metabolite profiles. Couples exhibited statistical correlations of varying strength for most physical, social, and behavioural characteristics including age, height, alcohol consumption, education, smoking status, physical activity, family history and ethnicity, with correlation coefficients ranging from 0.22 to 0.73. There was no evidence of within couple associations for BMI and weight, where the correlation coefficients were - 0.03 (95% CI - 0.14, 0.08) and 0.01 (95% CI - 0.10, 0.12), respectively. Within spousal associations of the metabolite measurements were all positive but with weak to modest magnitudes, with the median correlation coefficient across all 155 measures being 0.12 (range 0.01-0.37 and interquartile range 0.10-0.18). With just four having associations stronger than 0.3: docosahexaenoic acid (0.37, 95% CI 0.22, 0.52), omega-3 fatty acids (0.32, 95% CI 0.20, 0.43) histidine (0.32, 95% CI 0.23, 0.41) and pyruvate (0.32, 95% CI 0.22, 0.43). Infertile couples exhibit spousal similarities for a range of demographic and serum metabolite measures, supporting initial assortative mating, with diet-derived metabolites suggesting possible subsequent convergence of their individual metabolic profile.

Spousal similarities in cardiometabolic risk factors: A cross-sectional comparison between Dutch and Japanese data from two large biobank studies

BACKGROUND AND AIMS

Few studies have examined and compared spousal concordance in different populations. This study aimed to quantify and compare spousal similarities in cardiometabolic risk factors and diseases between Dutch and Japanese populations.

METHODS

This cross-sectional study included 28,265 Dutch Lifelines Cohort Study spouse pairs (2006-2013) and 5,391 Japanese Tohoku Medical Megabank Organization (ToMMo) Cohort Study pairs (2013-2016). Spousal similarities in cardiometabolic risk factors were evaluated using Pearson's correlation or logistic regression analyses adjusted for spousal age.

RESULTS

The husbands' and wives' average ages in the Lifelines and ToMMo cohorts were 50.0 and 47.7 years and 63.2 and 60.4 years, respectively. Significant spousal similarities occurred with all cardiometabolic risk factors and diseases of interest in both cohorts. The age-adjusted correlation coefficients ranged from 0.032 to 0.263, with the strongest correlations observed in anthropometric traits. Spousal odds ratios [95% confidence interval] for the Lifelines vs. ToMMo cohort ranged from 1.45 (1.36-1.55) vs. 1.20 (1.05-1.38) for hypertension to 6.86 (6.30-7.48) vs. 4.60 (3.52-6.02) for current smoking. An increasing trend in spousal concordance with age was observed for sufficient physical activity in both cohorts. For current smoking, those aged 20-39 years showed the strongest concordance between pairs in both cohorts. The Dutch pairs showed stronger similarities in anthropometric traits and lifestyle habits (smoking and drinking) than their Japanese counterparts.

CONCLUSIONS

Spouses showed similarities in several cardiometabolic risk factors among Dutch and Japanese populations, with regional and cultural influences on spousal similarities.

Gender Specificity of Spousal Concordance in the Development of Chronic Disease among Middle-Aged and Older Chinese Couples: A Prospective Dyadic Analysis

This study aimed to explore the gender specificity of spousal concordance in the development of chronic diseases among middle-aged and older Chinese couples. Data of 3420 couples were obtained from the China Health and Retirement Longitudinal Study (CHARLS). Multivariate logistic regression was used to analyze the incidence of chronic disease development over 4 years, conditional on the spousal baseline chronic disease status; and stepwise adjusting for the couples’ sociodemographic characteristics (i.e., age, education, retirement status and household income), and their individual lifestyle (i.e., smoking, drinking, exercise, social participation and BMI) all measured at baseline. The incidence of chronic diseases after 4 years of follow-up was 22.95% in the husbands (605/2636) and 24.71% in the wives (623/2521). Taking the couples’ baseline sociodemographic and lifestyle covariates into account, husbands whose wife had chronic diseases at baseline showed an increased risk of developing chronic diseases over 4 years (OR_adjusted = 1.24, 95%CI: 1.02, 1.51), but this risk was not statistically-significant for wives (OR_adjusted = 0.88, 95%CI: 0.71, 1.08). Our study identified gender specificity of spousal concordance in the development of chronic diseases among middle-aged and older Chinese couples. This finding may contribute to the design of couple-based intervention for disease prevention and management for community-dwelling older adults.

Marriage and reductions in men's alcohol, tobacco, and cannabis use

BACKGROUND

Psychoactive substance use is lower among married compared to divorced or unmarried men; yet, the nature of this effect remains unclear because becoming and staying married is potentially confounded with substance-related background familial and individual factors, like parental divorce and personality. The authors investigated the associations between marital status and substance use; how substance use changed across the transition to marriage; and whether marriage effects were likely to be causal.

METHOD

The sample included 1790 adults from male-male twin pairs from a population-based registry. Measures of marital status and alcohol, tobacco, and cannabis use came from Life History Calendars. Data were analyzed using regression, co-twin comparison, and within-person models. The latter models are tools for quasi-causal inference that control for familial and individual-level confounders.

RESULTS

Married men used less alcohol, tobacco, and cannabis than men who were divorced/separated or single. In analyses of substance use across the transition to marriage, men reduced their alcohol and cannabis use both before and after marriage, but their tobacco use only after marriage. These effects were largely robust in co-twin and within-person analyses.

CONCLUSIONS

Marriage was associated with substantial reductions in substance use compared to being divorced/separated or single, and these reductions began prior to marriage. The co-twin comparison and within-person models ruled out the alternative explanation that marriage effects were due to confounding background familial and individual factors. These results provide strong evidence that the social role expectations associated with marriage reduce psychoactive substance use.

Quantile-Specific Heritability of Intakes of Alcohol but not Other Macronutrients

Genetic heritability (h²) of alcohol use is reported to be greater in rural dwellers, distressed marriages, low socioeconomic status, in girls who are unmarried or lacking closeness with their parents or religious upbringing, in less-educated men, and in adolescents with peers using alcohol. However, these are all risk factors for heavy drinking, and the greater heritability could be due to quantile-dependent expressivity, i.e., h² dependent upon whether the phenotype (alcohol intake) is high or low relative to its distribution. Quantile regression showed that h² estimated from the offspring-parent regression slope increased significantly from lowest to highest gram/day of alcohol consumption (0.006 ± 0.001 per percent, P = 1.1 × 10^-7). Heritability at the 90th percentile of the sample distribution (0.557 ± 0.116) was 4.5-fold greater than at the 10th percentile (0.122 ± 0.037). Heritabilities for intakes of other macronutrients were not quantile-dependent. Thus quantile-dependent expressivity may explain the higher estimated heritability associated with risk factors for high alcohol consumption.

An Extended Twin-Pedigree Study of Different Classes of Voluntary Exercise Behavior

We investigated the familial clustering of different classes of voluntary regular exercise behavior in extended twin-family pedigrees. In contrast to the earlier work based on twin data only, this allowed us to estimate the contributions of shared household effects (C), additive (A), and non-additive (D) genetic effects on voluntary exercise behavior. To test whether shared household effects were inflated by assortative mating we examined the causes of spousal resemblance. For adolescent and adult participants (aged 16 to 65) in the Netherlands Twin Register we constructed 19,543 pedigrees which specified all relations among nuclear family members and larger families in the register (N = 50,690 individuals). Data were available on total weekly MET minutes spent on leisure time exercise, and on total weekly MET minutes spent on exercise activities in team-based, solitary, competitive, non-competitive, externally paced and internally paced exercise. We analyzed the data in the Mendel software package (Lange et al. in Bioinformatics 29(12):1568–1570, 2013) under multiple definitions of household sharing and used data from spouses of twins to test phenotypic assortment, social homogamy, and marital interaction as potential sources of spousal resemblance. Results confirmed the influence of genetic factors on the total volume of weekly exercise behavior throughout the life span. Broad sense heritability ranged from 34 to 41% (19–26% A, 12–21% D), and did not depend on the definition for household sharing. Engaging in team-based, competitive, externally paced activities (e.g., soccer) was ~ 13% more heritable than engaging in non-competitive, solitary activities (e.g., jogging). Having shared a household as siblings explained 4–8% of the variance in adult exercise behavior, whereas sharing a household by spouses yielded higher C estimates (20–24%), as it incorporates spousal resemblance. Spousal resemblance was explained by both social homogamy and marital interaction, with little evidence for phenotypic assortment. We conclude that both the amount of voluntary exercise behavior and the preference for specific classes of exercise activities in adults is explained by additive and non-additive genetic factors and unique environmental influences that include correlated exercise behavior of spouses.

Quantile-Specific Heritability may Account for Gene-Environment Interactions Involving Coffee Consumption

Estimated heritability of coffee intake ranges from 0.36 to 0.58, however, these point estimates assume that inherited effects are the same throughout the distribution of coffee intake, i.e., whether consumption is high or low relative to intake in the population. Quantile regression of 4788 child-parent pairs and 2380 siblings showed that offspring-parent and sibling concordance became progressively greater with increasing quantiles of coffee intake. Each cup/day increase in the parents' coffee intake was associated with an offspring increase of 0.020 ± 0.013 cup/day at the 10th percentile of the offsprings' coffee intake (slope ± SE, NS), 0.137 ± 0.034 cup/day at their 25th percentile (P = 5.2 × 10^-5), 0.159 ± 0.029 cup/day at the 50th percentile (P = 5.8 × 10^-8), 0.233 ± 0.049 cup/day at the 75th percentile (P = 1.8 × 10^-6), and 0.284 ± 0.054 cup/day at the 90th percentile (P = 1.2 × 10^-7). This quantile-specific heritability suggests that factors that distinguish heavier vs. lighter drinkers (smoking, male sex) will likely manifest differences in estimated heritability, as reported.

Genetic evidence for assortative mating on alcohol consumption in the UK Biobank

Alcohol use is correlated within spouse-pairs, but it is difficult to disentangle effects of alcohol consumption on mate-selection from social factors or the shared spousal environment. We hypothesised that genetic variants related to alcohol consumption may, via their effect on alcohol behaviour, influence mate selection. Here, we find strong evidence that an individual's self-reported alcohol consumption and their genotype at rs1229984, a missense variant in ADH1B, are associated with their partner's self-reported alcohol use. Applying Mendelian randomization, we estimate that a unit increase in an individual's weekly alcohol consumption increases partner's alcohol consumption by 0.26 units (95% C.I. 0.15, 0.38; P = 8.20 × 10^-6). Furthermore, we find evidence of spousal genotypic concordance for rs1229984, suggesting that spousal concordance for alcohol consumption existed prior to cohabitation. Although the SNP is strongly associated with ancestry, our results suggest some concordance independent of population stratification. Our findings suggest that alcohol behaviour directly influences mate selection.

Simulations and directed acyclic graphs explained why assortative mating biases the prenatal negative control design

OBJECTIVE

The negative control design can be used to provide evidence for whether a prenatal exposure-outcome association occurs by in utero mechanisms. Assortative mating has been suggested to influence results from negative control designs, although how and why has not yet been adequately explained. We aimed to explain why mutual adjustment of maternal and paternal exposure in regression models can account for assortative mating.

STUDY DESIGN AND SETTING

We used directed acyclic graphs to show how bias can occur when modeling maternal and paternal effects separately. We empirically tested our claims using a simulation study. We investigated how increasing assortative mating influences the bias of effect estimates obtained from models that do and do not use a mutual adjustment strategy.

RESULTS

In models without mutual adjustment, increasing assortative mating led to increased bias in effect estimates. The maternal and paternal effect estimates were biased by each other, making the difference between them smaller than the true difference. Mutually adjusted models did not suffer from such bias.

CONCLUSIONS

Mutual adjustment for maternal and paternal exposure prevents bias from assortative mating influencing the conclusions of a negative control design. We further discuss issues that mutual adjustment may not be able to resolve.

Hazardous alcohol consumption among spouses or partners of military service personnel: a systematic review of the literature

BACKGROUND

Alcohol misuse is particularly high among both the UK and US Armed Forces. As alcohol use among couples is associated, military spouses or partners may therefore be at a higher risk of acquiring hazardous drinking behaviours than people in relationships with other occupational groups.

METHOD

A literature review using a systematic approach was undertaken in four medical databases and supplemented with hand searches of specialist publications and reference lists. The prevalence of hazardous alcohol consumption among military spouses or partners was estimated and potential sociodemographic and military factors associated with this outcome were identified.

RESULTS

Nine papers met inclusion criteria, of which eight focused on female spouses or partners only. The limited evidence suggests hazardous alcohol consumption was not a common outcome among spouses or partners. None of the papers statistically compared the prevalence among spouses or partners to estimates from the general population and few reported associations with sociodemographic or military factors. Deployment abroad did not appear to be significantly associated with hazardous consumption, although increasing periods of separation from Service personnel may be associated with increased hazardous consumption among spouses or partners.

CONCLUSION

Limited evidence was found concerning the prevalence of hazardous alcohol consumption among military spouses or partners or which sociodemographic and military factors might be associated with this outcome. The a dominance of US studies means applying the estimates of these outcomes to other nations must be undertaken with care due to differences in cultural attitudes to alcohol as well as differences between military structure and operations between the US and other nations.

Concordance in the Health Behaviors of Couples by Age: A Cross-sectional Study

Objectives

To investigate concordance in the health behaviors of women and their partners according to age and to investigate whether there was a stronger correlation between the health behaviors of housewives and those of their partners than between the health behaviors of non-housewives and those of their partners.

Methods

We used data obtained from women participants in the 2015 Korea Community Health Survey who were living with their partners. The outcome variables were 4 health behaviors: smoking, drinking, eating salty food, and physical activity. The main independent variables were the partners’ corresponding health behaviors. We categorized age into 4 groups (19-29, 30-49, 50-64, and ≥ 65 years) and utilized multivariate logistic regression analysis, stratifying by age group. Another logistic regression analysis was stratified by whether the participant identified as a housewife.

Results

Data from 64 971 women older than 18 years of age were analyzed. Of the 4 health behaviors, the risk of smoking (adjusted odds ratio [aOR], 4.65; 95% confidence interval [CI], 3.93 to 5.49) was highest when the participant’s partner was also a smoker. Similar results were found for an inactive lifestyle (aOR, 2.56; 95% CI, 2.45 to 2.66), eating salty food (aOR, 2.48; 95% CI, 2.36 to 2.62); and excessive drinking (aOR, 1.89; 95% CI, 1.80 to 1.98). In comparison to non-housewives, housewives had higher odds of eating salty food.

Conclusions

The health behaviors of women were positively correlated with those of their partners. The magnitude of the concordance differed by age group.

The Origin of Spousal Resemblance for Alcohol Use Disorder

IMPORTANCE

Although spouses strongly resemble one another in their risk for alcohol use disorder (AUD), the causes of this association remain unclear.

OBJECTIVES

To examine longitudinally, in first marriages, the association of a first registration for AUD in one spouse with risk of registration in his or her partner and to explore changes in the risk for AUD registration in individuals with multiple marriages as they transition from a spouse with AUD to one without or vice versa.

DESIGN, SETTING, AND PARTICIPANTS

Population-wide Swedish registries were used to identify individuals born in Sweden between 1960 and 1990 who were married before the end of study follow-up on December 31, 2013. The study included 8562 marital pairs with no history of AUD registration prior to their first marriage and an AUD registration in 1 spouse during marriage and 4891 individuals with multiple marriages whose first spouse had no AUD registration and second spouse did or vice versa. Final statistical analyses were conducted from August 15 to September 1, 2017.

EXPOSURES

A spousal onset or history of AUD registration.

MAIN OUTCOMES AND MEASURES

Alcohol use disorder registration in national medical, criminal, or pharmacy registries.

RESULTS

Among the 8562 marital pairs (5883 female probands and 2679 male probands; mean [SD] age at marriage, 29.2 [5.7] years) in first marriages, the hazard ratio of AUD registration in wives immediately after the first AUD registration in their husbands was 13.82, which decreased 2 years later to 3.75. The hazard ratio of AUD registration in husbands after the first AUD registration in their wives was 9.21, which decreased 2 years later to 3.09. Among the 4891 individuals with multiple marriages (1439 women and 3452 men; mean [SD] age at first marriage, 25.5 [4.2] years), when individuals transitioned from a first marriage to a spouse with AUD to a second marriage to a spouse without AUD, the hazard ratio for AUD registration was 0.50 (95% CI, 0.42-0.59) in women and 0.51 (95% CI, 0.44-0.59) in men. After a first marriage to a spouse without AUD, the hazard ratio for AUD with a second marriage to a spouse with AUD was 7.02 (95% CI, 5.34-9.23) in women and 9.06 (95% CI, 7.55-10.86) in men. These patterns were modestly attenuated when moving from second to third marriages. Controlling for AUD registration prior to first marriage or between first and second marriages produced minimal changes in risk.

CONCLUSIONS AND RELEVANCE

The increase in risk for AUD registration in a married individual following a first AUD registration in the spouse is large and rapid. When an individual with serial spouses is married, in either order, to partners with vs without an AUD registration, the risk for AUD registration is substantially increased when the partner has an AUD registration and decreased when the partner does not have an AUD registration. These results suggest that a married individual's risk for AUD is directly and causally affected by the presence of AUD in his or her spouse.

Investigating spousal concordance of diabetes through statistical analysis and data mining

OBJECTIVE

Spousal clustering of diabetes merits attention. Whether old-age vulnerability or a shared family environment determines the concordance of diabetes is also uncertain. This study investigated the spousal concordance of diabetes and compared the risk of diabetes concordance between couples and noncouples by using nationally representative data.

METHODS

A total of 22,572 individuals identified from the 2002-2013 National Health Insurance Research Database of Taiwan constituted 5,643 couples and 5,643 noncouples through 1:1 dual propensity score matching (PSM). Factors associated with concordance in both spouses with diabetes were analyzed at the individual level. The risk of diabetes concordance between couples and noncouples was compared at the couple level. Logistic regression was the main statistical method. Statistical data were analyzed using SAS 9.4. C&RT and Apriori of data mining conducted in IBM SPSS Modeler 13 served as a supplement to statistics.

RESULTS

High odds of the spousal concordance of diabetes were associated with old age, middle levels of urbanization, and high comorbidities (all P < 0.05). The dual PSM analysis revealed that the risk of diabetes concordance was significantly higher in couples (5.19%) than in noncouples (0.09%; OR = 61.743, P < 0.0001).

CONCLUSIONS

A high concordance rate of diabetes in couples may indicate the influences of assortative mating and shared environment. Diabetes in a spouse implicates its risk in the partner. Family-based diabetes care that emphasizes the screening of couples at risk of diabetes by using the identified risk factors is suggested in prospective clinical practice interventions.

Alcohol use disorder and divorce: evidence for a genetic correlation in a population-based Swedish sample

AIMS

We tested the association between alcohol use disorder (AUD) and divorce; estimated the genetic and environmental influences on divorce; estimated how much genetic and environmental influences accounted for covariance between AUD and divorce; and estimated latent genetic and environmental correlations between AUD and divorce. We tested sex differences in these effects.

DESIGN

We identified twin and sibling pairs with AUD and divorce information in Swedish national registers. We described the association between AUD and divorce using tetrachorics and used twin and sibling models to estimate genetic and environmental influences on divorce, on the covariance between AUD and divorce and the latent genetic and environmental correlations between AUD and divorce.

SETTING

Sweden.

PARTICIPANTS

A total of 670 836 individuals (53% male) born 1940-1965.

MEASUREMENTS

Life-time measures of AUD and divorce.

FINDINGS

AUD and divorce were related strongly (males: r_tet  = +0.44, 95% CI = 0.43, 0.45; females r_tet  = +0.37, 95% CI = 0.36, 0.38). Genetic factors accounted for a modest proportion of the variance in divorce (males: 21.3%, 95% CI = 7.6, 28.5; females: 31.0%, 95% CI = 18.8, 37.1). Genetic factors accounted for most of the covariance between AUD and divorce (males: 52.0%, 95% CI = 48.8, 67.9; females: 53.74%, 95% CI = 17.6, 54.5), followed by non-shared environmental factors (males: 45.0%, 95% CI = 37.5, 54.9; females: 41.6%, 95% CI = 40.3, 60.2). Shared environmental factors accounted for a negligible proportion of the covariance (males: 3.0%, 95% CI = -3.0, 13.5; females: 4.75%, 95% CI = 0.0, 6.6). The AUD-divorce genetic correlations were high (males: rA = +0.76, 95% CI = 0.53, 0.90; females +0.52, 95% CI = 0.24, 0.67). The non-shared environmental correlations were modest (males: rE = +0.32, 95% CI = 0.31, 0.40; females: +0.27, 95% CI = 0.27, 0.36).

CONCLUSIONS

Divorce and alcohol use disorder are correlated strongly in the Swedish population, and the heritability of divorce is consistent with previous studies. Covariation between AUD and divorce results from overlapping genetic and non-shared environmental factors. Latent genetic and non-shared environmental correlations for alcohol use disorder and divorce are high and moderate.

Parallel contagion phenomenon of concordant mental disorders among married couples: a nationwide cohort study

BACKGROUND

The aggregation of mental disorders in couples, as reported by prior research, indicates the effect of familial environments and warrants attention. However, the concordant categories of mental disorders in couples remain unclear. This study investigated spousal concordance for the category of mental disorders among couples throughout Taiwan by using factors associated with such disorders.

METHODS

5643 couples in the 2002-2013 Taiwan National Health Insurance Research Database were analysed and compared with propensity-matched 5643 non-couples. Twelve independent variables, including spouse and shared characteristics, and the category of mental disorders were analysed, mainly by using multinomial logistic regression.

RESULTS

The determined prevalence rates for concordant categories of mental disorder were 0.19% for affective disorders, 6.96% for anxiety disorders, and 3.15% of other mental disorders. Multinomial logistic regression results revealed that two spouses were significantly more likely to be diagnosed with the same category of the aforementioned mental disorders (ORs=2.914, 1.776 and 1.727, respectively). Other associated factors included gender, age, occupation, comorbidity and region. The odds of concordances were significantly higher in couples than in non-couples.

CONCLUSIONS

A category of mental disorder in one spouse is a determinant of that in the other spouse. This study extended the emotional contagion theory to the phenomenon of parallel contagion to reflect the three concordances, suggesting a direction of family-based mental health intervention, particularly prevention for the same category of mental disorders in couples. Policymakers should strengthen the coping strategies of the caring spouse and external support system to psychiatrically vulnerable families.

Relationship factors and couples' engagement in sun protection

Individuals may be more motivated to adopt health practices if they consider the benefits of these behaviors for their close relationships. The goal of this study was to examine couple concordance with sun protection and use the interdependence and communal coping theory to evaluate the role of relationship factors in sun protection. One hundred and eighty-four married couples aged 50 years and older completed measures of objective skin cancer risk, perceived risk, sun protection benefits, relationship-centered motivations for sun protection, discussions about sun protection, and sun protection. A mediational model was evaluated. Results indicated a high level of couple concordance. Partners who adopted a relationship-centered motivation for sun protection were more likely to discuss sun protection with one another, and partners who discussed sun protection together were more likely to engage in sun protection. One partner's attitude about personal risk and sun protection benefits was associated with the other partner's sun protection. Wives had higher relationship-centered motivation and discussed sun protection more with their husbands. Behavioral interventions may benefit from encouraging couples to discuss sun protection and encouraging married individuals to consider the benefits of sun protection for their relationship and for their spouse's health.

High Job Demands, Job Strain, and Iso-Strain are Risk Factors for Sick Leave due to Mental Disorders: A Prospective Swedish Twin Study With a 5-Year Follow-Up

OBJECTIVE

To investigate whether psychosocial work environment and health behaviors are risk factors for sick leave due to mental disorders, and whether familial confounding (genetics and shared environment) explains the associations.

METHODS

Respondents (n = 11,729), given to complete a questionnaire in 2004 to 2006, were followed up approximately 5 years for sick leave spells due to mental disorders, using national registry data. Data were analyzed using logistic regression, and conditional logistic regression for twin pairs discordant for sick leave (cotwin control).

RESULTS

High job demands, job strain, and iso-strain were independent risk factors for sick leave due to mental disorders. Familial factors seem to be of importance in the associations between job support, smoking, a combination of unhealthy behaviors and sick leave.

CONCLUSIONS

Improving the psychosocial work environment may be effective in preventing sick leave due to mental disorders.

Relationship factors in skin self-examination among couples

OBJECTIVE

Individuals may be more motivated to adopt health-promoting practices if they consider the benefits of these behaviours for their close relationships. The goal of this study was to use the interdependence theory to evaluate the role of relationship factors in skin self-examination (SSE).

DESIGN

The study adopted a cross-sectional survey design.

METHODS

One hundred and eighty-four married couples aged 50 years and older completed measures of skin cancer worry, SSE benefits, SSE barriers, relationship-centred motivations for SSE, discussions about SSE, and SSE practices in the past year.

RESULTS

Couples who discussed SSE with one another were more likely to engage in it. Couples who adopted a relationship-centred motivation for SSE were more likely to discuss SSE, and, ultimately, engage in SSE. One partner's beliefs were associated with the other partner's SSE. Women who adopted a relationship-centred motivation for SSE had husbands who discussed SSE more and also had husbands who were more likely to conduct SSE. Men who adopted a relationship-centred motivation for SSE did not have wives who reported that they discussed SSE more with their husbands and/or wives who were more likely to conduct SSE. These findings suggest that wives' relationship beliefs and discussions with their husbands may have a stronger association with their husbands' SSE practices than the associations between husbands' relationship beliefs and discussions with their wives' SSE practices.

CONCLUSIONS

Behavioural interventions may benefit from encouraging couples to discuss SSE and consider the benefits of SSE for their relationship and for their spouse's health. Statement of contribution What is already known on this subject? Previous studies have shown that people are more motivated to adopt health-promoting behaviours if they consider the benefits of such behaviours for their close relationships. However, little is known about the role of the marital relationship in the engagement in skin self-examination (SSE) practices. What does this study add? This study builds on prior research evaluating the role of relationship factors in cancer screening and surveillance practices. Couples who discuss SSE with one another are more likely to engage in it. Couples who consider the benefits of engaging in SSE for their relationship are more likely to discuss skin examinations and engage in them.

Understanding The Role of Mate Selection Processes in Couples' Pair-Bonding Behavior

Couples are similar in their pair-bonding behavior, yet the reasons for this similarity are often unclear. A common explanation is phenotypic assortment, whereby individuals select partners with similar heritable characteristics. Alternatively, social homogamy, whereby individuals passively select partners with similar characteristic due to shared social backgrounds, is rarely considered. We examined whether phenotypic assortment and/or social homogamy can contribute to mate similarity using a twin-partner design. The sample came from the Twin and Offspring Study in Sweden, which included 876 male and female monozygotic and same-sex dizygotic twins plus their married or cohabitating partners. Results showed that variance in pair-bonding behavior was attributable to genetic and nonshared environmental factors. Furthermore, phenotypic assortment accounted for couple similarity in pair-bonding behavior. This suggests that individuals' genetically based characteristics are involved in their selection of mates with similar pair-bonding behavior.

Spousal resemblance for smoking: Underlying mechanisms and effects of cohort and age

BACKGROUND

In this study we ask why spouses resemble each other in smoking behaviour and assess if such resemblance depends on period of data collection or age. Spousal similarity may reflect different, not mutually exclusive, processes. These include phenotypic assortment (choice of spouse is based on phenotype) or social homogamy at the time spouses first meet, and marital interaction during the relationship.

METHODS

Ever and current smoking were assessed between 1991 and 2013 in surveys of the Netherlands Twin Register for 14,230 twins and 1,949 of their spouses (mean age 31.4 [SD=14.0]), and 11,536 parents of twins (53.4 [SD=8.6]). Phenotypic assortment and social homogamy were examined cross-sectionally by calculating the probability of agreement between twins and their spouses, twins and their co-twin's spouse and spouses of both twins as a function of zygosity. Marital interaction was tested by investigating the association between relationship duration and spousal resemblance.

RESULTS

Between 1991 and 2013 smoking declined in all age groups for both genders. Spousal resemblance for ever and current smoking was higher when data were more recent. For ever smoking, a higher age of men was associated with lower spousal resemblance. Phenotypic assortment was supported for both smoking measures, but social homogamy could not be excluded. No effect of marital interaction was found.

CONCLUSIONS

Differences in smoking prevalence across time and age influence spousal similarity. Individuals more often choose a spouse with similar smoking behaviour (phenotypic assortment) causing higher genotypic similarity between them. Given the heritability of smoking this increases genetic risk of smoking in offspring.

Health, health behaviors, and health dissimilarities predict divorce: results from the HUNT study

Background

Poor health and health behaviors are associated with divorce. This study investigates the degree to which six health indicators and health behaviors among husbands and wives are prospectively related to divorce, and whether spousal similarities in these factors are related to a reduced risk of marital dissolution. Theoretically, a reduced risk is possible, because spousal similarity can help the couple’s adaptive processes.

Methods

The data come from a general population sample (19,827 couples) and 15 years of follow-up data on marital dissolution. The following characteristics were investigated: Poor subjective health, obesity, heavy drinking, mental distress, lack of exercise, and smoking. Associations between these characteristics among husbands and wives and later divorce were investigated with Cox proportional hazards regression analyses.

Results

All the investigated characteristics except obesity were associated with marital dissolution. Moreover, spousal similarities in four of these characteristics (heavy drinking, mental distress, no exercise, and smoking) reduced the risk of divorce, compared to the combined main effects of husbands and wives. Nevertheless, couples concordant in these health issues still had higher risks of divorce than couples without these characteristics.

Conclusion

Couples with similar health and health behavior are at a lower risk of divorce than are couples who are dissimilar in health. Health differences may thus be seen as vulnerabilities or stressors, supporting a health mismatch hypothesis. This study demonstrates that people who are similar to each other are more likely to stay together. Harmonizing partners’ health behaviors may be a target in divorce prevention.

Phenotype refinement strengthens the association of AHR and CYP1A1 genotype with caffeine consumption

Two genetic loci, one in the cytochrome P450 1A1 (CYP1A1) and 1A2 (CYP1A2) gene region (rs2472297) and one near the aryl-hydrocarbon receptor (AHR) gene (rs6968865), have been associated with habitual caffeine consumption. We sought to establish whether a more refined and comprehensive assessment of caffeine consumption would provide stronger evidence of association, and whether a combined allelic score comprising these two variants would further strengthen the association. We used data from between 4,460 and 7,520 women in the Avon Longitudinal Study of Parents and Children, a longitudinal birth cohort based in the United Kingdom. Self-report data on coffee, tea and cola consumption (including consumption of decaffeinated drinks) were available at multiple time points. Both genotypes were individually associated with total caffeine consumption, and with coffee and tea consumption. There was no association with cola consumption, possibly due to low levels of consumption in this sample. There was also no association with measures of decaffeinated drink consumption, indicating that the observed association is most likely mediated via caffeine. The association was strengthened when a combined allelic score was used, accounting for up to 1.28% of phenotypic variance. This was not associated with potential confounders of observational association. A combined allelic score accounts for sufficient phenotypic variance in caffeine consumption that this may be useful in Mendelian randomization studies. Future studies may therefore be able to use this combined allelic score to explore causal effects of habitual caffeine consumption on health outcomes.

Non-random mating and convergence over time for alcohol consumption, smoking, and exercise: the Nord-Trøndelag Health Study

Spouses tend to have similar lifestyles. We explored the degree to which spouse similarity in alcohol use, smoking, and physical exercise is caused by non-random mating or convergence. We used data collected for the Nord-Trøndelag Health Study from 1984 to 1986 and prospective registry information about when and with whom people entered marriage/cohabitation between 1970 and 2000. Our sample included 19,599 married/cohabitating couples and 1,551 future couples that were to marry/cohabitate in the 14-16 years following data collection. All couples were grouped according to the duration between data collection and entering into marriage/cohabitation. Age-adjusted polychoric spouse correlations were used as the dependent variables in non-linear segmented regression analysis; the independent variable was time. The results indicate that spouse concordance in lifestyle is due to both non-random mating and convergence. Non-random mating appeared to be strongest for smoking. Convergence in alcohol use and smoking was evident during the period prior to marriage/cohabitation, whereas convergence in exercise was evident throughout life. Reduced spouse similarity in smoking with relationship duration may reflect secular trends.

Romantic partner selection and socialization of young adolescents' substance use and behavior problems

This study examined romantic partner selection and socialization of substance use (cigarettes, alcohol) and behavior problems among a sample of 78 young adolescents (6th-8th graders) over eleven months. Adolescent and romantic partner behaviors were assessed before and after relationships were initiated via school records and self-report. Most selection and socialization effects were apparent for the eighth grade adolescents (at Time 1). Prior to their relationship, eighth graders and romantic partners were alike on alcohol use. In contrast, romantic socialization effects emerged for eighth graders' cigarette use and behavior problems. The nature of the partner socialization effects depended on the combination of adolescents' and partners' pre-relationship behaviors. Eighth graders who dated partners with fewer problems showed the greatest instability in their behavior problems and partner behavior predicted greater decreased in problem behaviors among adolescents with more problems. The implications of these findings are discussed within the broader context of adolescent peer relationships.

Exercise participation in adolescents and their parents: evidence for genetic and generation specific environmental effects

Individual differences in adolescent exercise behavior are to a large extent explained by shared environmental factors. The aim of this study was to explore to what extent this shared environment represents effects of cultural transmission of parents to their offspring, generation specific environmental effects or assortative mating. Survey data on leisure-time exercise behavior were available from 3,525 adolescent twins and their siblings (13-18 years) and 3,138 parents from 1,736 families registered at the Netherlands Twin Registry. Data were also available from 5,471 adult twins, their siblings and spouses similar in age to the parents. Exercise participation (No/Yes, using a cut-off criterion of 4 metabolic equivalents and 60 min weekly) was based on questions on type, frequency and duration of exercise. A model to analyze dichotomous data from twins, siblings and parents including differences in variance decomposition across sex and generation was developed. Data from adult twins and their spouses were used to investigate the causes of assortative mating (correlation between spouses = 0.41, due to phenotypic assortment). The heritability of exercise in the adult generation was estimated at 42%. The shared environment for exercise behavior in adolescents mainly represents generation specific shared environmental influences that seem somewhat more important in explaining familial clustering in girls than in boys (52 versus 41%). A small effect of vertical cultural transmission was found for boys only (3%). The remaining familial clustering for exercise behavior was explained by additive genetic factors (42% in boys and 36% in girls). Future studies on adolescent exercise behavior should focus on identification of the generation specific environmental factors.

The crown of love: intimate relations and alcohol use in adolescence

BACKGROUND

Remarkably, little attention has been paid to the role of intimate partners and their drinking behavior in relation to adolescent alcohol use. In the current study, we examined associations between adolescent alcohol use and romantic partners' drinking behavior.

METHODS

A total of 428 families, consisting of both parents and two adolescents (aged 13.4 and 15.2 at Time 1) participated in a prospective study with four annual waves. Correlations and multivariate regressions were used to examine (1) similarity in drinking behaviors of adolescents and intimate partners, (2) whether alcohol use of partners prospectively predicts adolescent alcohol consumption, and (3) whether adolescents who consume alcohol select partners over time who show similar drinking behaviors.

RESULTS

(1) Frequency of alcohol consumption of adolescents and of their romantic partners correlated significantly. (2) Alcohol use of partners was not predictive of adolescent alcohol consumption over time, if previous levels of alcohol consumption were taken into account. (3) Adolescents acquired partners with similar drinking behaviors. Gender effects were found; adolescent girls, but not boys, were more likely to become involved with partners who also frequently consumed alcohol.

CONCLUSIONS

Regarding alcohol consumption, adolescents and their intimate partners were relatively similar in alcohol use. This resemblance is best explained by adolescents' selection of future partner on the basis of alcohol consumption. Less indication was found for influence effects, perhaps due to the transient nature of most adolescent romantic relationships.

Familial resemblance of borderline personality disorder features: genetic or cultural transmission?

Borderline personality disorder is a severe personality disorder for which genetic research has been limited to family studies and classical twin studies. These studies indicate that genetic effects explain 35 to 45% of the variance in borderline personality disorder and borderline personality features. However, effects of non-additive (dominance) genetic factors, non-random mating and cultural transmission have generally not been explored. In the present study an extended twin-family design was applied to self-report data of twins (N = 5,017) and their siblings (N = 1,266), parents (N = 3,064) and spouses (N = 939) from 4,015 families, to estimate the effects of additive and non-additive genetic and environmental factors, cultural transmission and non-random mating on individual differences in borderline personality features. Results showed that resemblance among biological relatives could completely be attributed to genetic effects. Variation in borderline personality features was explained by additive genetic (21%; 95% CI 17-26%) and dominant genetic (24%; 95% CI 17-31%) factors. Environmental influences (55%; 95% CI 51-60%) explained the remaining variance. Significant resemblance between spouses was observed, which was best explained by phenotypic assortative mating, but it had only a small effect on the genetic variance (1% of the total variance). There was no effect of cultural transmission from parents to offspring.

Genetics of coffee consumption and its stability

BACKGROUND

Coffee is a highly popular drink associated with the pathogenesis of several diseases and the use of tobacco and alcohol. Considering the worldwide consumption, coffee has a substantial effect on individual wellbeing and public health. The role of genetic factors contributing to interindividual differences and their stability in coffee use is not well known.

AIMS

We analysed the heritability of coffee consumption and its stability in a large population-based sample of Finnish twins.

DESIGN

In 1975 and 1981 a postal questionnaire on coffee consumption was sent to all Finnish same-sex twin pairs born before 1958. Responses were obtained from 10 716 complete twin pairs in 1975 (3409 monozygotic and 7307 dizygotic), of whom 8124 also responded in 1981. The data were analysed using classical twin modelling based on linear structural equations.

FINDINGS

Additive genetic and unique environmental factors affected coffee drinking, whereas shared environmental factors did not show any effect. Heritability of coffee consumption, adjusted for age and sex, was estimated as 0.56 in 1975 and 0.45 in 1981. Coffee consumption showed a moderate correlation between these two time-points (r = 0.58 in men and 0.55 in women). Genetic factors affecting coffee consumption were stable: additive genetic correlations were 0.84 in men and 0.83 in women, whereas unique environmental correlations were moderate (0.45 and 0.36). Additive genetic factors had the highest contribution in young adults.

CONCLUSIONS

Coffee consumption is affected by both additive genetic and unique environmental factors, each of which plays an almost equally important role. The long-term stability of coffee consumption is affected mainly by a stable set of additive genetic factors.

Marital resemblance for obsessive-compulsive, anxious and depressive symptoms in a population-based sample

BACKGROUND

Resemblance between spouses can be due to phenotypic assortment, social homogamy and/or marital interaction. A significant degree of assortment can have consequences for the genetic architecture of a population. We examined the existence and cause(s) of assortment for obsessive-compulsive (OC), anxious and depressive symptoms in a population-based twin-family sample.

METHOD

OC, anxious and depressive symptoms were measured in around 1400 twin-spouse pairs and >850 parent pairs. Correlations of twins and their spouse, twin and co-twin's spouse, spouses of both twins and parents of twins were obtained to consider phenotypic assortment versus social homogamy as possible causes of marital resemblance. The association of length of relationship with marital resemblance was also investigated. Finally, we examined whether within-trait or cross-trait processes play a primarily role in marital resemblance.

RESULTS

Small but significant within-trait correlations of between 0.1 and 0.2 were seen for spouse similarity in OC, anxious and depressive symptoms. Cross-correlations were significant but lower. There was no correlation between length of relationship and marital resemblance. From the pattern of correlations for twin-spouse, co-twin-spouse and spouses of both twins, phenotypic assortment could not be distinguished from social homogamy. Both within- and cross-assortment processes play a role in marital resemblance.

CONCLUSIONS

Small within- and across-trait correlations exist for OC, anxious and depressive symptoms. No evidence for marital interaction was found. Spouse correlations are small, which makes it difficult to distinguish between social homogamy and phenotypic assortment. It is unlikely that correlations of this size will have a large impact on genetic studies.