Familial [corrected] transmission of coronary heart disease: a cohort study of 80,214 Swedish adoptees linked to their biological and adoptive parents

Genetic and Nongenetic Components of Stroke Family History: A Population Study of Adopted and Nonadopted Individuals

Background Genetic and nongenetic factors account for the association of family history with disease risk. Comparing adopted and nonadopted individuals provides an opportunity to disentangle those factors. Methods and Results We examined associations between family history of stroke and heart disease with incident stroke and myocardial infarction (MI) in 495 640 UK Biobank participants (mean age, 56.5 years; 55% women) stratified by childhood adoption status (5747 adoptees). We estimated hazard ratios (HRs) per affected family member, and for polygenic risk scores in Cox models adjusted for baseline age and sex. A total of 12 518 strokes and 23 923 MIs occurred over a 13-year follow-up. In nonadoptees, family history of stroke and heart disease was associated with increased stroke and MI risk, with the strongest association of family history of stroke for incident stroke (HR, 1.16 [95% CI, 1.12-1.19]) and family history of heart disease for incident MI (HR, 1.48 [95% CI, 1.45-1.50]). In adoptees, family history of stroke associated with incident stroke (HR, 1.41 [95% CI, 1.06-1.86]), but family history of heart disease was not associated with incident MI (P>0.5). Polygenic risk scores showed strong disease-specific associations in both groups. In nonadoptees, the stroke polygenic risk score mediated 6% risk between family history of stroke and incident stroke, and the MI polygenic risk score mediated 13% risk between family history of heart disease and incident MI. Conclusions Family history of stroke and heart disease increases risk for their respective conditions. Family history of stroke contains substantial potentially modifiable nongenetic risk, indicating a need for novel prevention strategies, whereas family history of heart disease represents predominantly genetic risk.

Genetic and non-genetic components of family history of stroke and heart disease: a population-based study among adopted and non-adopted individuals

Background

It is increasingly clear that genetic and non-genetic factors account for the association of family history with disease risk in offspring. We sought to distinguish the genetic and non-genetic contributions of family history of stroke and heart disease on incident events by examining adopted and non-adopted individuals.

Methods

We examined associations between family history of stroke and heart disease with incident stroke and myocardial infarction (MI) in 495,640 participants of the UK Biobank (mean age 56.5 years, 55% female) stratified by early childhood adoption status into adoptees (n=5,747) and non-adoptees (n=489,893). We estimated hazard ratios (HRs) per affected nuclear family member, and for polygenic risk scores (PRS) for stroke and MI in Cox models adjusted for baseline age and sex.

Results

12,518 strokes and 23,923 MIs occurred over a 13-year follow-up. In non-adoptees, family history of stroke and heart disease were associated with increased stroke and MI risk, with the strongest association of family history of stroke for incident stroke (HR 1.16 [1.12, 1.19]) and family history of heart disease for incident MI (HR 1.48 [1.45, 1.50]). In adoptees, family history of stroke associated with incident stroke (HR 1.41 [1.06, 1.86]), but family history of heart disease did not associate with incident MI (p>0.5). PRS showed strong disease-specific associations in adoptees and non-adoptees. In non-adoptees, the stroke PRS mediated 6% risk between family history of stroke and incident stroke, and the MI PRS mediated 13% risk between family history of heart disease and MI.

Conclusions

Family history of stroke and heart disease increase risk for their respective conditions. Family history of stroke contains a substantial proportion of potentially modifiable non-genetic risk, indicating a need for further research to elucidate these elements for novel prevention strategies, whereas family history of heart disease represents predominantly genetic risk.

Familial transmission of chronic obstructive pulmonary disease in adoptees: a Swedish nationwide family study

OBJECTIVES

Familial clustering of chronic obstructive pulmonary disease (COPD) is well established, but the familial risk of COPD has not been determined among adoptees. The aim was to determine whether the familial transmission of COPD is related to disease in biological and/or adoptive parents.

DESIGN

Historic cohort study.

PARTICIPANTS

80,214 (50% females).

METHODS

The Swedish Multi-Generation Register was used to follow all Swedish-born adoptees born in 1932-2004 (n=80,214) between 1 January 1964 and 31 December 2010 for COPD (n=1978). The risk of COPD was estimated in adoptees with at least one biological parent with COPD but no adoptive parent with COPD (n=162) compared with adoptees without a biological or adoptive parent with COPD. The risk of COPD was also determined in adoptees with at least one adoptive parent but no biological parent with COPD (n=110), and in adoptees with both affected biological and adoptive parents (n=162).

PRIMARY OUTCOME MEASURE

COPD in adoptees.

RESULTS

Adoptees with COPD in at least one biological parent but no adoptive parent were more likely to have COPD than adoptees without a biological or adoptive parent with COPD (standardised incidence ratio, SIR=1.98 (95% CI 1.69 to 2.31)). The familial SIR for adoptees with both a biological parent and an adoptive parent with COPD was 1.68 (95% CI 1.39 to 2.00). Adoptees with at least one adoptive parent with COPD but no biological parent with COPD were not at an increased risk of COPD (SIR=1.12 (95% CI 0.92 to 1.35)).

CONCLUSIONS

The findings of the study show that the familial transmission of COPD is associated with COPD in biological but not adoptive parents, suggesting that genetic or early life factors are important in the familial transmission of COPD.

Fatalism moderates the relationship between family history of cardiovascular disease and engagement in health-promoting behaviors among at-risk rural Kentuckians

PURPOSE

In rural communities that experience high rates of cardiovascular disease (CVD) morbidity and mortality, family history education may enhance risk awareness and support engagement in healthy behaviors but could also engender fatalism. This study was conducted to assess if the relationship between family history and adherence to healthy lifestyle behaviors is moderated by fatalism.

METHODS

Baseline data were obtained from 1,027 adult participants in the HeartHealth in Rural Kentucky study. Multiple linear regression was used to determine whether fatalism moderated the relationship between high-risk family history of CVD and adherence to healthy lifestyle behaviors, controlling for sociodemographic variables and CVD risk factors. The relationship between family history and healthy behaviors was assessed for subgroups of participants divided according to the upper and lower quartiles of fatalism score.

FINDINGS

The relationship between high-risk family history of CVD and adherence to healthy behaviors was moderated by fatalism. Among those with the highest quartile of fatalism scores, high-risk family history predicted greater adherence to healthy behaviors, while among those in the lowest quartile, and among those with the middle 50% of fatalism scores, there was no association between family history and healthy behavior scores.

CONCLUSIONS

Family history education can provide people at increased risk for CVD important information to guide health practices. This may be particularly relevant for those with a high degree of fatalistic thinking. In rural communities with limited health resources, family history education, combined with assessment of fatalism, may support better targeted interventions to enhance engagement in healthy behaviors.

Familial Transmission of Venous Thromboembolism

Background—

Venous thromboembolism (VTE) clusters in families, but the familial risk of VTE has not been determined among adoptees. The aim was to disentangle the contributions of genetic and environmental factors to the familial transmission of VTE.

Methods and Results—

The Swedish Multi-Generation Register was used to follow all Swedish-born adoptees born from 1932 to 2004 (n=80,214) between January 1, 1964, and December 31, 2010, for VTE. The risk of VTE was estimated in adoptees with ≥1 biological parent with VTE compared with adoptees without a biological parent with VTE. The risk of VTE was also estimated in adoptees with ≥1 adoptive parent with VTE compared with adoptees without an adoptive parent with VTE. Adoptees with ≥1 biological parent with VTE (n=137) were more likely to have VTE than adoptees without a biological parent with VTE (standardized incidence ratio) 1.51 (95% confidence interval, 1.27–1.79). The standardized incidence ratio for VTE was highest for adoptees with a biological parent diagnosed with VTE before the age of 50 years (standardized incidence ratio=2.03, 1.24–3.14). In contrast, adoptees with ≥1 adoptive parent with VTE (n=156) were not at increased risk of VTE (standardized incidence ratio=1.07, 0.91–1.25).

Conclusions—

These novel findings suggest that genetic factors make a stronger contribution to the familial transmission of VTE from parents to offspring than family environmental factors.

Familial risk of early and late onset cancer: nationwide prospective cohort study

OBJECTIVE

To determine whether familial risk of cancer is limited to early onset cases.

DESIGN

Nationwide prospective cohort study.

SETTING

Nationwide Swedish Family-Cancer Database.

PARTICIPANTS

All Swedes born after 1931 and their biological parents, totalling >12.2 million individuals, including >1.1 million cases of first primary cancer.

MAIN OUTCOME MEASURES

Familial risks of the concordant cancers by age at diagnosis.

RESULTS

The highest familial risk was seen for offspring whose parents were diagnosed at an early age. Familial risks were significantly increased for colorectal, lung, breast, prostate, and urinary bladder cancer and melanoma, skin squamous cell carcinoma, and non-Hodgkin's lymphoma, even when parents were diagnosed at age 70-79 or 80-89. When parents were diagnosed at more advanced ages (≥ 90), the risk of concordant cancer in offspring was still significantly increased for skin squamous cell carcinoma (hazard ratio 1.9, 95% confidence interval 1.4 to 2.7), colorectal (1.6, 1.2 to 2.0), breast (1.3, 1.0 to 1.6), and prostate cancer (1.3, 1.1 to 1.6). For offspring with a cancer diagnosed at ages 60-76 whose parents were affected at age <50, familial risks were not significantly increased for nearly all cancers.

CONCLUSION

Though the highest familial risks of cancer are seen in offspring whose parents received a diagnosis of a concordant cancer at earlier ages, increased risks exist even in cancers of advanced ages. Familial cancers might not be early onset in people whose family members were affected at older ages and so familial cancers might have distinct early and late onset components.