Age, period and cohort trends in drug abuse hospitalizations within the total Swedish population (1975-2010)

The number of episodes of major psychiatric and substance use disorders as an index of genetic risk and genetic heterogeneity

We investigate whether number of episodes (NoEs) meaningfully reflect genetic risk and genetic heterogeneity for five primary disorders-Drug Use Disorder (DUD), Alcohol Use Disorder (AUD), Major Depression (MD), Bipolar Disorder (BD), and Schizophrenia (SZ) ascertained from Swedish population registries. We utilize Genetic Risk Ratios (GRR)-defined as the ratio of the genetic risk for secondary disorders to the genetic risk for the primary disorder-derived from Family Genetic Risk Scores (FGRS). For all five primary disorders, genetic risk rose robustly with increasing NoEs. For both AUD and DUD, the GRR for all six secondary disorders-selected to have a likely genetic relationship with the particular primary disorder-declined with increasing NoEs so that cases of AUD and DUD with high versus low NoEs had both a higher genetic risk and a purer genetic signal. With MD, genetic risk maximized at an intermediate NoEs. While the GRRs for AUD and DUD in MD cases dropped sharply with increasing NoEs, GRR for BD increased. For BD, genetic risk rose sharply with increasing NoEs while for all secondary disorders the GRRs showed a mixture of modest increases and decreases. Like AUD and DUD, but even more markedly, selecting BD cases with high rates of recurrence would produce a sample with a high overall genetic risk and a relatively homogeneous genetic signal. For SZ, genetic risk rose moderately with increases in NoEs. GRRs for other non-affective psychoses (ONAP) and autism spectrum disorder (ASD) fell quite slowly with increasing NoEs, and more rapidly for other secondary disorders. Cases of SZ with high recurrence rates had a high genetic risk and a relatively pure signal, albeit with contributions from ONAP and ASD. In summary, NOEs are a robust index of genetic risk and genetic heterogeneity across our primary disorders with important inter-disorder differences.

The Impact of the Good Behavior Game on Risk for Drug Use Disorder in an Agent-Based Model of Southern Sweden

OBJECTIVE

Drug use disorder (DUD) is a worldwide problem, and strategies to reduce its incidence are central to decreasing its burden. This investigation seeks to provide a proof of concept for the ability of agent-based modeling to predict the impact of the introduction of an effective school-based intervention, the Good Behavior Game (GBG), on reducing DUD in Scania, Sweden, primarily through increasing school achievement.

METHOD

We modified an existing agent-based simulation model of opioid use disorder to represent DUD in Scania County, southern Sweden. The model represents every individual in the population and is calibrated with the linked individual data from multiple sources including demographics, education, medical care, and criminal history. Risks for developing DUD were estimated from the population in Scania. Scenarios estimated the impact of introducing the GBG in schools located in disadvantaged areas.

RESULTS

The model accurately reflected the growth of DUD in Scania over a multiyear period and reproduced the levels of affected individuals in various socioeconomic strata over time. The GBG was estimated to improve school achievement and lower DUD registrations over time in males residing in disadvantaged areas by 10%, reflecting a decrease of 540 cases of DUD. Effects were considerably smaller in females.

CONCLUSIONS

This work provides support for the impact of improving school achievement on long-term risks of developing DUD. It also demonstrated the value of using simulation modeling calibrated with data from a real population to estimate the impact of an intervention applied at a population level.

Post-traumatic stress disorder and drug use disorder: examination of aetiological models in a Swedish population-based cohort

Background: There are two primary phenotypic models of comorbidity between post-traumatic stress disorder (PTSD) and drug use disorder (DUD), i.e. self-medication (PTSD precedes and causes DUD) and susceptibility (DUD precedes and causes PTSD). We sought to clarify the longitudinal relationship between PTSD and DUD, while examining sex differences.Method: We used approximately 23 years of longitudinal data from Swedish population registries to conduct two complementary statistical models: Cox proportional hazard models (N ≈ 1.5 million) and a cross-lagged panel model (N ≈ 3.8 million).Results: Cox proportional hazards models, adjusting for cohort and socioeconomic status, found strong evidence for the self-medication hypothesis, as PTSD predicted increased risk for DUD among both women [hazard ratio (HR) = 5.34, 95% confidence interval (CI) 5.18, 5.51] and men (HR = 3.65, 95% CI 3.54, 3.77), and moreover, that the PTSD to DUD association was significantly higher among women (interaction term 0.68, 95% CI 0.65, 0.71). The results of the susceptibility model were significant, but not as strong as the self-medication model. DUD predicted risk for PTSD among both women (HR = 2.43, 95% CI 2.38, 2.50) and men (HR = 2.55, 95% CI 2.50, 2.60), and HR was significantly higher in men (interaction term 1.05, 95% CI 1.02, 1.08). Investigating the pathways simultaneously in the cross-lagged model yielded support for both pathways of risk. The cross-paths instantiating the susceptibility model (0.10-0.22 in females, 0.12-0.19 in males) were mostly larger than those capturing the self-medication model (0.01-0.16 in females, 0.04-0.22 in males).Conclusions: We demonstrate that the relationship between PTSD and DUD is bidirectional, with evidence that future research should prioritize examining specific pathways of risk that may differ between men and women.

Cross-generational transmission of genetic risk for alcohol and drug use disorders: the impact of substance availability on the specificity of genetic risk

BACKGROUND

Among individuals with alcohol use disorder (AUD) and drug use disorder (DUD), is their genetic liability and its specificity moderated by substance availability?

METHODS

Offspring (born 1960-1995) and their biological parents from three family types [not-lived-with (NLW) biological father, mother and adoptive] and their AUD and DUD diagnoses were ascertained from Swedish national registers. Parent-offspring resemblance was calculated by tetrachoric correlation.

RESULTS

In Swedes born from 1960 to 1995, prevalence rates of AUD were stable while DUD rates increased substantially. Best-estimate tetrachoric correlations (±95% confidence intervals) between AUD in biological parents and AUD and DUD in their offspring were, respectively, +0.19 (0.18-0.20) and +0.18 (0.17-0.20). Parallel results from DUD in parents to AUD and DUD in children were +0.12 (0.10-0.13) and +0.27 (0.26-0.28). When divided into older and younger cohorts, the specificity of DUD transmission increased substantially over time, while the genetic correlation between AUD and DUD significantly decreased.

CONCLUSIONS

Raised when alcohol was the preferred substance of abuse and illicit drugs highly stigmatized, AUD in parents reflected a general liability to substance use disorders, as they transmitted similar genetic risk for AUD and DUD to their children raised when both substances were widely available and relatively acceptable. DUD in parents, by contrast, reflected a more specific liability to DUD and, when transmitted to offspring, produced a considerably stronger risk for DUD than for AUD that increased over time. The magnitude and specificity of the genetic liability to psychoactive substances can be influenced by the availability of that substance.

Spatiotemporal patterns of drug use disorder in Sweden assessed using population-based registries

BACKGROUND

Drug Use Disorder (DUD) is a major contributor to world-wide morbidity and mortality. The extensive national registers in Sweden provide the basis for a study of spatial and temporal patterns of DUD onset and recurrence in Sweden from 2001-2015.

METHODS

To identify patterns of DUD over space, time and gender for Swedish individuals aged 15-35, space-time clustering using SaTScan was applied. We used yearly information on residential locations in Demographic Statistical Areas (DeSO) for all of Sweden. The clustering analysis used a Poisson probability model and a null hypothesis that the expected number of cases in each DeSO was proportional to the population size of DeSOs. As SaTScan results can be unstable, steps were taken to determine stable clusters and to refine and optimize cluster size. Results for each gender-register combination were compared to the results of spatial clustering using Gi* statistics. The space-time scanning model was also run with an adjustment for neighborhood socioeconomic status to determine DUD prevalence as it relates to education, income, unemployment and receipt of social welfare.

RESULTS

DUD prevalence increased over time. Males yielded more significant clusters than females for both criminal and medical registers. Female DUD prevalence rates increased over time, especially after 2012. Higher correlations in DUD rates existed across the two registers than across gender. Male clusters were present from 2004 onwards while female-criminal clusters appeared after 2007, and female-medical clusters not until 2010. By 2013, clusters existed for all gender-register combinations. Male-criminal clusters were concentrated in Stockholm, Göteborg and Malmö as were male and female-medical clusters. Neighborhood SES was more highly related to the distribution of criminal than medical DUD clusters. A persistent gap in core clusters was identified in Stockholm in an area with notably high SES.

CONCLUSIONS

Persistent hotspots of DUD in Sweden were confirmed as well as new and emerging hotspots, especially in Stockholm, Göteborg and Malmö. Higher correlations existed in DUD rates across registers than across gender. The findings are useful for monitoring the current drug problem and for identifying drivers underlying patterns of spread and important causal pathways to DUD.

The intergenerational persistence of opioid dependence: Evidence from administrative data

To address the opioid crisis, it is crucial to understand its origins. We provide descriptive evidence for the intergenerational persistence of opioid dependence. Our analysis is based on administrative data covering the universe of Austrian births from 1984 to 1990. We consider prescription opioids and a new proxy for addiction to illicit opioids. We find that, if at least one parent is using illicit opioids, the likelihood of the child using increases from 1% to 7%. For prescription opioids, we observe an increase from 3.6% to 6.7%. Both associations are stable and do not change when controlling for environmental variables.

Birth order and health events attributable to alcohol and narcotics in midlife: A 25-year follow-up of a national Swedish birth cohort and their siblings

Higher birth order is associated with increased risks of adverse health outcomes attributable to alcohol or narcotics in adolescence, but it remains unclear whether these observed birth order effects are also present in midlife. Drawing on a national Swedish cohort born in 1953 and their siblings, we estimate associations between birth order and alcohol- or narcotics-attributable hospitalization or death with a 25-year follow-up to assess whether birth order differences are observed during this life course period. Health events attributable to alcohol or narcotics use were identified using the Swedish National Patient and Cause of Death registers, respectively. We apply Cox proportional hazards models to estimate average birth order differences in hazards for alcohol- or narcotics-attributable hospitalization or death between ages 30 and 55. We estimate birth order differences between families, and use two fixed-effects approaches to estimate birth order differences within families and within families of the same type. Bivariate results indicate increased hazards for both outcomes with higher birth order; however, these results are no longer observed after adjustment for familial background characteristics in all models. Our results thereby show limited evidence for birth order differences in midlife. This study highlights that shared factors within the family of origin may be stronger predictors of adverse health outcomes attributable to substance use among siblings during this life course period. Future research should disentangle the contributions of the social environment within the family of origin for adverse health outcomes attributable to alcohol or narcotics among siblings.

•

We estimate birth order differences for alcohol or narcotics use outcomes between ages 30-55.

•

Birth order differences are not observed for alcohol- or narcotics-attributable events in midlife.

•

Family background characteristics may be stronger predictors of these outcomes.

Forecasting Obesity and Type 2 Diabetes Incidence and Burden: The ViLA-Obesity Simulation Model

Background

Obesity is a major public health problem affecting millions of Americans and is considered one of the most potent risk factors for type 2 diabetes. Assessing future disease burden is important for informing policy-decision making for population health and healthcare.

Objective

The aim of this study was to develop a computer model of a cohort of children born in Los Angeles County to study the life course incidence and trends of obesity and its effect on type 2 diabetes mellitus.

Methods

We built the Virtual Los Angeles cohort—ViLA, an agent-based model calibrated to the population of Los Angeles County. In particular, we developed the ViLA-Obesity model, a simulation suite within our ViLA platform that integrated trends in the causes and consequences of obesity, focusing on diabetes as a key obesity consequence during the life course. Each agent within the model exhibited obesity- and diabetes-related healthy and unhealthy behaviors such as sugar-sweetened beverage consumption, physical activity, fast-food consumption, fresh fruits, and vegetable consumption. In addition, agents could gain or lose weight and develop type 2 diabetes mellitus with a certain probability dependent on the agent's socio-demographics, past behaviors and past weight or type 2 diabetes status. We simulated 98,230 inhabitants from birth to age 65 years, living in 235 neighborhoods.

Results

The age-specific incidence of obesity generally increased from 10 to 30% across the life span with two notable peaks at age 6–12 and 30–39 years, while that of type 2 diabetes mellitus generally increased from <2% at age 18–24 to reach a peak of 25% at age 40–49. The 16-year risks of obesity were 32.1% (95% CI: 31.8%, 32.4%) for children aged 2–17 and 81% (95% CI: 80.8%, 81.3%) for adults aged 18–65. The 48-year risk of type 2 diabetes mellitus was 53.4% (95% CI: 53.1%, 53.7%) for adults aged 18–65.

Conclusion

This ViLA-Obesity model provides an insight into the future burden of obesity and type 2 diabetes mellitus in Los Angeles County, one of the most diverse places in the United States. It serves as a platform for conducting experiments for informing evidence-based policy-making.

Patterns of drug overdose deaths in Kuwait from 2014 to 2018

Background

Kuwait is an Arabian Gulf couFntry with a population of around 4.4 million as of 2020. In recent years, government based news agencies have commonly exposed drug smuggling plots that were foiled by local authorities. We attempted to study the patterns of drug overdose deaths in Kuwait, which we believe is a good method to address the effect of illicit drug use in the country.

Methodology

All cases that were signed out as drug overdose death were collected from the General department of criminal evidence. The relationship between demographic factors and drug types were analyzed using various statistical methodologies.

Results

344 victims were identified from 2014 to 2018. The majority of whom were Kuwaiti nationals (67%) and the average age of death was 38. Hawalli governorate had the highest number of cases, while Jahra governorate had the least. Morphine appeared to be the most common drug found in the victims post mortem (79.9%) followed by benzodiazepines (43%). Our study has an extremely low female number of victims (2.6%). Some substances that are commonly abused globally eg heroin and cocaine were rarely recovered in our study. The number of cases have had an increase over the study period with the highest number of cases in 2018.

Conclusion

The current study is the first of its kind in Kuwait and one of the first in the middle east region. It is evident that illicit drug use and subsequent drug overdose deaths are on a rise in Kuwait and government agencies need to put a strategic plan to address and reduce this problem.

Short- and long-term follow-up outcomes of patients with Brucella endocarditis: a systematic review of 207 Brucella endocarditis Cases

Brucella endocarditis is a fatal complication and the most frequent cause of death for human brucellosis. This study aimed to systematically review the literature on the follow-up outcomes of Brucella endocarditis and analyze the determinants affecting the follow-up outcomes. The databases PubMed, Web of Science, Embase, and Cochrane were searched using keywords and suitable combinations. All studies reporting the follow-up outcomes of Brucella endocarditis were included. Finally, a total of 76 studies (207 patients), including cases or case series, were included. The event rate for patients who underwent short- and long-term follow-up was 12.0% (2 relapsed and 1 died) and 8.1% (6 relapsed and 8 died), respectively. The differences in outcomes between different age groups (18–39, 40–59, and ≥60) were significant (P < 0.05, P = 0.035). The outcomes of the 18–39 age group were worse than those of the 40–59 age group (OR, 0.277; 95% CI, 0.103–0.748; P = 0.011). Accordingly, follow-up (both short- and long-term follow-up) is essential for Brucella endocarditis patients, especially for younger patients (18–39 years) in the first 6 months after treatment. The burden of Brucella endocarditis related complications were immense. Further studies are needed to explore age-based epidemiology of Brucella endocarditis and the exact influencing factors of the follow-up outcomes.

Association of Tourette Syndrome and Chronic Tic Disorder With Subsequent Risk of Alcohol- or Drug-Related Disorders, Criminal Convictions, and Death: A Population-Based Family Study

BACKGROUND

It remains unclear if individuals with Tourette syndrome (TS) or chronic tic disorder (CTD) have an elevated risk of subsequent substance misuse.

METHODS

In this population-based cohort study, we investigated the association between ICD diagnoses of TS/CTD and substance misuse outcomes, accounting for psychiatric comorbidity and familial factors. The cohort included all individuals living in Sweden at any time between January 1, 1973, and December 31, 2013. Substance misuse outcomes were defined as an ICD code of substance use-related disorder or cause of death, or as a substance use-related criminal conviction in the nationwide registers.

RESULTS

The cohort included 14,277,199 individuals, of whom 7832 had a TS/CTD diagnosis (76.3% men). TS/CTD was associated with an increased risk of any subsequent substance misuse outcomes (adjusted hazard ratio [aHR], 3.11; 95% confidence interval [CI], 2.94-3.29), including alcohol-related disorder (aHR, 3.45; 95% CI, 3.19-3.72), drug-related disorder (aHR, 6.84; 95% CI, 6.32-7.40), substance-related criminal convictions (aHR, 2.56; 95% CI, 2.36-2.77), and substance-related death (aHR, 2.54; 95% CI, 1.83-3.52). Excluding psychiatric comorbidities had little effect on the magnitude of the associations, with the exception of attention-deficit/hyperactivity disorder, which attenuated the risk of any substance misuse outcomes (aHR, 2.00; 95% CI, 1.82-2.19). The risk of any substance misuse outcomes in individuals with TS/CTD was substantially attenuated but remained significant when compared with their unaffected siblings (aHR, 1.74; 95% CI, 1.53-1.97).

CONCLUSIONS

TS/CTD were associated with various types of subsequent substance misuse outcomes, independently of psychiatric comorbidity and familial factors shared between siblings. Screening for drug and alcohol use should become part of the standard clinical routines, particularly in patients with comorbid attention-deficit/hyperactivity disorder.

Cross-classified multilevel models (CCMM) in health research: A systematic review of published empirical studies and recommendations for best practices

Recognizing that health outcomes are influenced by and occur within multiple social and physical contexts, researchers have used multilevel modeling techniques for decades to analyze hierarchical or nested data. Cross-Classified Multilevel Models (CCMM) are a statistical technique proposed in the 1990s that extend standard multilevel modeling and enable the simultaneous analysis of non-nested multilevel data. Though use of CCMM in empirical health studies has become increasingly popular, there has not yet been a review summarizing how CCMM are used in the health literature. To address this gap, we performed a scoping review of empirical health studies using CCMM to: (a) evaluate the extent to which this statistical approach has been adopted; (b) assess the rationale and procedures for using CCMM; and (c) provide concrete recommendations for the future use of CCMM. We identified 118 CCMM papers published in English-language literature between 1994 and 2018. Our results reveal a steady growth in empirical health studies using CCMM to address a wide variety of health outcomes in clustered non-hierarchical data. Health researchers use CCMM primarily for five reasons: (1) to statistically account for non-independence in clustered data structures; out of substantive interest in the variance explained by (2) concurrent contexts, (3) contexts over time, and (4) age-period-cohort effects; and (5) to apply CCMM alongside other techniques within a joint model. We conclude by proposing a set of recommendations for use of CCMM with the aim of improved clarity and standardization of reporting in future research using this statistical approach.

Parent-offspring transmission of drug abuse and alcohol use disorder: Application of the multiple parenting relationships design

With complete genealogical and cohabitation information, new genetic-epidemiological designs can be developed to clarify causes of parent-offspring transmission. We propose the Multiple Parenting Relationships (MPR) Design and apply it to drug abuse (DA) and alcohol use disorder (AUD). Using national Swedish registries, we identified four kinds of informative parents with multiple children with whom they had different genetic and/or rearing relationships. These types had children for whom they provided: (a) genes (G) plus rearing (R), G only and R only; (b) G + R and G only; (c) G only and R only; and (d) G + R and R only. We identified DA and AUD cases from national registries in over 475,000 informative parent-offspring pairs. Controlling for parental resemblance for DA or AUD, all estimates were statistically homogeneous across family types. The weighted average tetrachoric correlation (SE) for DA for G + R, R only and G only relationships were, respectively, +0.21 (0.01), +0.10 (0.02), and +0.16 (0.02). Parallel results for AUD were +0.16 (0.01), +0.04 (0.02), and +0.14 (0.01). Analyses within families with affected parents showed significantly higher disorder risks in offspring with a G + R versus an R only relationship. The MPR design is complementary to other methods, especially adoption and triparental designs, in clarifying the sources of cross-generational transmission. Consistent with results from these other designs applied to the Swedish population, we find that for DA and AUD, parent-offspring resemblance was strongest for G + R relationships, intermediate for G only relationships and weakest but significant for R only relationships.

Changes over time in marijuana use, deviant behavior and preference for risky behavior among US adolescents from 2002 to 2014: testing the moderating effect of gender and age

BACKGROUND AND AIMS

Among adolescents, risk preference and deviant behaviors are associated with marijuana use, which exhibit substantial historical trends. We examined (1) trends, (2) effect modification by sex and age, (3) associations of marijuana use with deviant behaviors and risk preferences and (4) differences by sex, age and year.

DESIGN

Adjusted logistic and relative risk regression models, using data from the 2002-14 National Survey on Drug Use and Health, annual cross-sectional surveys of US households.

SETTING

United States.

PARTICIPANTS

A nationally representative sample of adolescents aged 12-17 years (n = 230 452).

MEASUREMENTS

We estimated associations between past-year marijuana use [self-reported using computer-assisted personal interviewing/audio computer-assisted self-interviewing (CAPI/ACASI)], deviant behavior (i.e. selling drugs; stealing; attacking someone) and risk preference (i.e. getting a kick; testing oneself).

FINDINGS

Marijuana use, deviant behaviors and risk preferences declined among adolescents from 2002 to 2014. There were no significant sex or age differences in the decline of marijuana use over time. There were sex [sold drugs: β = 0.90, 95% confidence interval (CI) = 0.75, 1.04] and age (attacked someone: β = 0.32, 95% CI = 0.22, 0.42) differences in the prevalence of deviant behaviors, and trends over time differed by sex and age for attacking someone.

CONCLUSIONS

While marijuana use, deviant behavior and risk preferences among US adolescents declined from 2002 to 2014, associations have remained stable, with marijuana use positively associated with deviant behaviors and risk preferences.

Past-month cannabis use among U.S. individuals from 2002-2015: An age-period-cohort analysis

BACKGROUND

Cannabis is the most commonly used illicit drug among U.S. adolescents and adults, but little is known about factors that drive trends in cannabis use prevalence. To better understand drivers of these trends, we aimed to estimate age, period, and cohort effects on past-month cannabis use among U.S. individuals age 12 and older from 2002 to 2015.

METHODS

We conducted an age-period-cohort analysis on past-month cannabis use among participants ages 12 and older using the National Survey on Drug Use and Health (NSDUH), an annual cross-sectional nationally-representative survey of drug use. Additionally, we examined how age, period, and cohort effects differed across gender. Participants (n = 779,799) self-reported cannabis patterns using a computer-assisted telephone interview (CATI).

RESULTS

Past-month cannabis use in this population increased from 6.0% in 2002 to 8.1% in 2015. Distinct age, period, and cohort effects were observed. Compared to participants ages 12-13, participants ages 18-21 (PR: 16.8, 95% CI: 15.6, 18.1) and 22-25 (PR: 13.2, 95% CI: 12.2, 14.4) had dramatically higher prevalence of past-month cannabis use. Compared to participants in 2002, participants in 2014 (PR: 1.2, 95% CI: 1.1, 1.4) and 2014 (PR: 1.2, 95% CI: 1.1, 1.4) had slightly higher prevalence of past-month cannabis use. Compared to the 1940s birth cohort, the 1950s birth cohort (PR: 1.8, 95% CI: 1.5, 2.2) had a higher prevalence of past-month cannabis use.

CONCLUSIONS

Past-month cannabis use is prevalent and increasing among U.S. adults. Distinct age, period, and cohort effects are at play, though age effects are strongest.

Familial transmission of externalizing syndromes in extended Swedish families

Risk for criminal behavior (CB), alcohol use disorder (AUD), and drug abuse (DA) are known to be familial. We know less about their transmission across three generations. We examined 844,109 probands born in Sweden 1980-1990, their parents, aunts/uncles, and grandparents for registration in population-based registers for CB, AUD, and DA. Mean tetrachoric relative-proband correlations (95% CIs) were highest for DA (+0.24, 0.24-0.25), followed by CB (+0.23,0.22-0.23) and AUD (+0.17, 0.16-0.17). AUD and CB were relatively stably transmitted across generations, while DA resemblance among relatives was stronger in the younger generations. For all three syndromes, male-male transmission was modestly stronger than female-female. Cross-sex transmission was significantly weaker than same-sex transmission for DA and CB but not AUD. Risk to probands with only an affected grandparent or aunt/uncle were increased 50-60% for CB and AUD, and 70-100% for DA. Parallel figures for affected parents only and parents + grandparent or aunt/uncle were 2-3-fold and 4-5-fold for CB and AUD, and 4-5-fold and 6-7-fold for DA. CB, AUD, and DA are all substantially familial in the Swedish population with the transmission across three generations stable for CB and AUD but not DA. Modest quantitative sex effects are seen in the familial transmission of CB, AUD, and DA, and qualitative sex effects for CB and DA. Risk prediction in offspring is orderly with affection status in grandparental and avuncular relationships adding appreciably to that from the parental generation.

Sources of Parent-Child Transmission of Drug Abuse: Path Analyses of Not-Lived-With Parental, Stepparental, Triparental, and Adoptive Families

To clarify the origins of parent-child resemblance for drug abuse (DA), using national Swedish data, we fit path models to information on DA in parents and children from six informative family types: i) not-lived-with father, ii) not-lived-with mother, iii) stepfather, iv) stepmother, v) triparental, and vi) adoptive. From these families, we estimated parent-offspring resemblance reflecting the effects of genes + rearing, genes only, and rearing only. The estimates of parent-offspring correlations were statistically homogenous across family types. The weighted estimate of the father-offspring correlation for DA for genes + rearing, genes-only, and rearing-only relationships were, respectively, +0.26, +0.19, and +0.06. Parallel figures for mother-offspring relationships were +0.19, +0.13, and +0.09. In both genes + rearing and genes-only parent-offspring relationships, DA correlations were stronger for fathers than for mothers. Both genetic and environmental factors contribute substantially to parent-offspring resemblance for DA and seem to be additive.

Transmission of alcohol use disorder across three generations: a Swedish National Study

BACKGROUND

While risk for alcohol use disorder (AUD) is correlated in twins, siblings and parent-offspring pairs, we know little of how this syndrome is transmitted across three generations.

METHOD

We examined 685 172 individuals born in Sweden from 1980 to 1990 with four grandparents, and both parents alive in 1980. AUD was assessed in all these individuals from nationwide medical, criminal and pharmacy registries.

RESULTS

AUD was stably transmitted across three generations. Parent-child and grandparent-grandchild tetrachoric correlations equaled +0.25 and +0.12, respectively. Grandchild AUD risk did not vary as a function of the sex of the parent or grandparent. However, from grandparents and parents, transmission to grandchildren was stronger in same-sex than opposite-sex pairs. Compared with a grandchild with unaffected parents and grandparents, risk for AUD with a grandparent but no parent affected, a parent but no grandparent affected or both affected increased approximately 70% and 3 and 4-fold, respectively. Grandchildren with ⩾2 grandparents affected had a 40% greater AUD risk than those with only one affected. Tetrachoric correlations for AUD between offspring and great-aunts/uncles, and aunts/uncles equaled +0.06 and +0.13, respectively.

CONCLUSIONS

The transmission of AUD in Sweden across three generations is relatively stable. An orderly pattern of resemblance is seen with correlations declining by approximately 50% between first and second, and second and third-degree relatives. While the transmission of risk from affected male and female relatives does not differ, we find consistent evidence for greater resemblance in same-sex v. opposite-sex across generational pairs of relatives.

Environmental clustering of drug abuse in households and communities: multi-level modeling of a national Swedish sample

PURPOSE

Both epidemiological and genetically informative studies indicate that shared environmental influences contribute to resemblance in siblings for drug abuse (DA). To what degree do these influences arise from living in the same household versus residing in the same community?

METHODS

We performed a cross-classified multi-level logistic regression on all individuals born in Sweden 1975-1990 (N = 1558,654). We assessed the proportion of the total population variation in DA that was due to household versus community effects controlling for genetic resemblance. DA was assessed from medical, criminal and pharmacy records.

RESULTS

Expressed as an intraclass correlation (ICC), the combined household/community effects accounted for ~8 % of the total population variation in DA. The variance attributed to the community was greater than that seen for household (4.5 versus 3.4 %). In males, the variance components were slightly larger and nearly equal at the community (5.3 %) and household level (5.1 %). In females, household effects (4.8 %) were stronger than those arising from the community (3.2 %).

CONCLUSION

In the total population and among males, community effects on DA were somewhat more potent than household effects. However, in females, household effects on DA were stronger than community effects. In Sweden, shared environmental effects for DA arise both at the household and at the community level. Community effects on DA are more potent in males than in females.

A population-based Swedish Twin and Sibling Study of cannabis, stimulant and sedative abuse in men

BACKGROUND

Prior studies, utilizing interview-based assessments, suggest that most of the genetic risk factors for drug abuse (DA) are non-specific with a minority acting specifically on risk for abuse of particular psychoactive substance classes. We seek to replicate these findings using objective national registry data.

METHODS

We examined abuse of cannabis, stimulants (including cocaine) and sedatives ascertained from national Swedish registers in male-male monozygotic (1720 pairs) and dizygotic twins (1219 pairs) combined with near-age full siblings (76,457 pairs) to provide sufficient power. Modeling was performed using Mx.

RESULTS

A common pathway model fitted better than an independent pathway model. The latent liability to DA was highly heritable but also influenced by shared environment. Cannabis, stimulant and sedative abuse all loaded strongly on the common factor. Estimates for the total heritability for the three forms of substance abuse ranged from 64 to 70%. Between 75 and 90% of that genetic risk was non-specific, coming from the common factor with the remainder deriving from substance specific genetic risk factors. By contrast, all of the shared environmental effects, which accounted for 18-20% of the variance in liability, were non-specific.

CONCLUSIONS

In accord with prior studies based on personal interviews, the large preponderance of genetic risk factors for abuse of specific classes of psychoactive substance are non-specific. These results suggest that genetic variation in the primary sites of action of the psychoactive drugs, which differ widely across most drug classes, play a minor role in human individual differences in risk for DA.

Trends in tobacco consumption in three different birth cohorts of elderly of São Paulo, Brazil

BACKGROUND

The effects of birth cohorts reflect the historical differences in physical and social environments. The objectives of the present study were to describe the tobacco consumption and to evaluate the behavioral trends with respect to smoking in three different birth cohorts of a population-based sample of elderly individuals.

METHODS

A series of three cross-sectional studies conducted with elderly individuals of 60-64 years of age interviewed in 2000 (birth cohort 1936-1940; n=427), 2006 (birth cohort 1942-1946; n=298) and 2011 (birth cohort 1947-1951; n=355) in a population-based sample from the city of São Paulo, Brazil. The interviewees were participating in a prospective cohort study entitled Health, Well-Being and Aging (Saúde, Bem-Estar e Envelhecimento [SABE]). Data on tobacco consumption were self-reported and interviewees were then classified as never smokers, former smokers or current smokers. Linear model for categorical data was used to test differences on tobacco consumption between three birth elderly cohorts.

FINDINGS

Men were more likely than women to be smokers. Being evangelical and having more schooling constituted protective factors against smoking. Regarding trends, the tobacco consumption of the men did not change in any of the three cohorts studied (p=0.7454), whereas there was an increase in the number of women smokers, principally former smokers, over the periods evaluated (p=0.0189).

CONCLUSIONS

These results suggest that the anti-smoking policies implemented in Brazil were effective in women of this age group; however, different prevention strategies are required to target elderly men.

Unexpected adverse childhood experiences and subsequent drug use disorder: a Swedish population study (1995-2011)

AIMS

Exposure to extraordinary traumatic experience is one acknowledged risk factor for drug use. We aim to analyse the influence of potentially life-changing childhood stressors, experienced second-hand, on later drug use disorder in a national population of Swedish adolescent and young adults (aged 15-26 years).

DESIGN

We performed Cox proportional hazard regression analyses, complemented with co-relative pair comparisons.

SETTING

Sweden.

PARTICIPANTS

All individuals in the Swedish population born 1984-95, who were registered in Sweden at the end of the calendar year that they turned 14 years of age. Our follow-up time (mean 6.2 years; range 11 years) started at the year they turned 15 and continued to December 2011 (n = 1,409,218).

MEASUREMENTS

Our outcome variable was drug use disorder, identified from medical, legal and pharmacy registry records. Childhood stressors, as per DSM-IV stressor criteria, include death of an immediate family member and second-hand experience of diagnoses of malignant cancer, serious accidental injury and victim of assault. Other covariates include parental divorce, familial psychological wellbeing and familial drug and alcohol use disorders.

FINDINGS

After adjustment for all considered confounders, individuals exposed to childhood stressors 'parental death' or 'parental assault' had more than twice the risk of drug use disorder than those who were not [hazard ratio (HR) = 2.63 (2.23-3.09) and 2.39 (2.06-2.79), respectively].

CONCLUSIONS

Children aged under 15 years who experience second-hand an extraordinary traumatic event (such as a parent or sibling being assaulted, diagnosed with cancer or dying) appear to have approximately twice the risk of developing a drug use disorder than those who do not.