The familial aggregation of atopic diseases and depression or anxiety in children

Background

Children with asthma and atopic diseases have an increased risk of depression or anxiety. Each of these diseases has strong genetic and environmental components; therefore, it seems likely that there is a shared liability rather than causative risk.

Objective

To investigate the existence and nature of familial aggregation for the comorbidity of atopic diseases and depression or anxiety.

Methods

Participants came from the Childhood and Adolescent Twin Study in Sweden (CATSS), n = 14 197. Current and ever asthma, eczema, hay fever and food allergy were reported by parents. Internalizing disorders were identified using validated questionnaires. Familial co‐aggregation analysis compared monozygotic (MZ) twins and same‐sex dizygotic (DZ) twins for atopic disease in 1 twin with internalizing disorder in the other to test for genetic liability. Several familial liability candidates were also tested including parental education, recent maternal psychological stress, childhood family trauma and parental country of birth.

Results

Familial co‐aggregation analysis found that if 1 twin had at least 1 current atopic disease the partner twin was at risk of having an internalizing disorder regardless of their own atopic status (adjusted OR 1.22 (95% CI 1.08, 1.37). Similar results were found for each atopic disease ever and current. MZ associations were not higher than DZ associations, suggesting that the liability is not genetic in nature. Including other familial candidates to the models made little difference to effect estimates.

Conclusions and Clinical Relevance

Atopic diseases and depression or anxiety tend to occur together in families; therefore, when treating for 1 disease, the physician should consider comorbidity in both the individual and the individual's siblings. We did not find evidence to support a genetic explanation for comorbidity, and further exploration is needed to disentangle the environmental and epigenetic reasons for familial aggregation.

Depression or anxiety in adult twins is associated with asthma diagnosis but not with offspring asthma

BACKGROUND

Asthma is common in both children and adults in the Western world, just like anxiety and depression. While some research has revealed that these diseases might share important environmental and pathophysiological aspects, the exact mechanisms still remain unclear.

OBJECTIVE

To study the correlation firstly between depression or anxiety and asthma diagnosis in adult twins and secondly the association between parental depression or anxiety and offspring asthma in children of twins.

METHODS

In total, 24 685 adult twins aged 20-47 years were interviewed or completed a Web-based questionnaire and their children were identified through the Multi-Generation Register. Asthma diagnosis was obtained from the Patient Register and the Prescribed Drug Register. Assessment of depression and anxiety was obtained from questionnaires using Center for Epidemiologic Studies Depression Scale (CES-D), major depression and generalized anxiety disorder (GAD) from DSM-IV. The association between depression or anxiety and asthma was analyzed with logistic regression adjusting for confounders in twins and offspring. To address genetic and familial environmental confounding, we performed a cotwin analysis using disease-discordant twin pairs.

RESULTS

We found an association between asthma and CES-D, major depression and GAD, for example adjusted OR for major depression and register-based asthma 1.56 (1.36-1.79). Most of the point estimates remained in the co-twin control analysis, indicating that the association was likely not due to genetic or familial environmental factors. There was no association between parental depression and/or anxiety and asthma diagnosis in the offspring which implies lack of genetic confounding.

CONCLUSIONS

We found an association between own asthma diagnosis and anxiety or depression, but not with offspring asthma. Our results indicate that the associations were not due to confounding from genes or environment shared by the twins.

Twins' risk of childhood asthma mediated by gestational age and birthweight

BACKGROUND

Children born with low gestational age (GA) or low birthweight (BW) are at increased risk of asthma. Twins as compared to singletons are on average more likely to be born with lower GA and BW and have been hypothesized to comprise a high-risk population for asthma. Many previous studies have not accounted for potential confounders or mediators.

OBJECTIVE

To investigate the association between twinship and childhood asthma or early life wheeze and identify potential mediators, such as GA/BW.

METHODS

The study population consisted of two cohorts including all children born in Sweden from 1 January 1993 to 1 June 2001 (n = 756,363 singletons, n = 22,478 twins) and 1 July 2005 to 31 December 2009 (n = 456,239 singletons, n = 12,872 twins). Asthma was defined using validated register-based outcomes of diagnosis or medication. The data were analysed using logistic (older cohort) and Cox regression (younger cohort). Adjusted models incorporated potential confounding or mediating factors including gestational age and birthweight.

RESULTS

In the younger cohort, the crude hazard ratio (HR) of asthma medication after 1.5 years of age was 1.12 (95% CI 1.01-1.23), and fully adjusted HR was 0.80, 95% CI 0.72-0.89. Crude HR of asthma diagnosis in the same age group was 1.14 (95% CI 0.99-1.30), fully adjusted 0.78 (0.68-0.98). Adjusted analyses in the older group yielded similar results.

CONCLUSIONS

Twins were at significantly higher unadjusted risk of asthma or early life wheeze compared to singletons in the younger, but not in the older cohort. Associations attenuated following adjustment for GA/BW, suggesting that GA/BW mediates the effect of twinship on asthma risk. After adjustments, twins were at lower risk of asthma outcomes, possibly due to unmeasured confounding.

Heritability and confirmation of genetic association studies for childhood asthma in twins

BACKGROUND

Although the genetics of asthma has been extensively studied using both quantitative and molecular genetic analysis methods, both approaches lack studies specific to the childhood phenotype and including other allergic diseases. This study aimed to give specific estimates for the heritability of childhood asthma and other allergic diseases, to attempt to replicate findings from genomewide association studies (GWAS) for childhood asthma and to test the same variants against other allergic diseases.

METHODS

In a cohort of 25 306 Swedish twins aged 9 or 12 years, data on asthma were available from parental interviews and population-based registers. The interviews also inquired about wheeze, hay fever, eczema, and food allergy. Through structural equation modeling, the heritability of all phenotypes was calculated. A subset of 10 075 twins was genotyped for 16 single nucleotide polymorphisms (SNPs) selected from previous GWAS; these were first tested for association with asthma and significant findings also against the other allergic diseases.

RESULTS

The heritability of any childhood asthma was 0.82 (95% CI 0.79-0.85). For the other allergic diseases, the range was approximately 0.60-0.80. Associations for six SNPs with asthma were replicated, including rs2305480 in the GSDMB gene (OR 0.80, 95% CI 0.74-0.86, P = 1.5*10(-8) ; other significant associations all below P = 3.5*10(-4) ). Of these, only rs3771180 in IL1RL1 was associated with any other allergic disease (for hay fever, OR 0.64, 95% CI 0.53-0.77, P = 2.5*10(-6) ).

CONCLUSION

Asthma and allergic diseases of childhood are highly heritable, and these high-risk genetic variants associated specifically with childhood asthma, except for one SNP shared with hay fever.

Impact of asthma medication and familial factors on the association between childhood asthma and attention-deficit/hyperactivity disorder: a combined twin- and register-based study: Epidemiology of Allergic Disease

BACKGROUND

Asthma and attention-deficit/hyperactivity disorder (ADHD) are prevalent in childhood and may cause functional impairment and stress in families. Previous research supports an association between asthma and ADHD in children, but several aspects of this relationship are unclear.

OBJECTIVE

Our aim was to study whether the association between asthma and ADHD is restricted to either the inattentive or the hyperactive/impulsive symptoms of ADHD, to explore the impact of asthma severity and asthma medication and the contribution of shared genetic and environmental risk factors on the asthma-ADHD relationship.

METHODS

Data on asthma, ADHD, zygosity and possible confounders were collected from parental questionnaires at 9 or 12 years on 20 072 twins through the Swedish Twin Register, linked to the Swedish Medical Birth Register, the National Patient Register and the Prescribed Drug Register. The association between asthma and ADHD, the impact of asthma severity and medication, was assessed by generalized estimating equations. Cross-twin-cross-trait correlations (CTCT) were estimated to explore the relative importance of genes and environment for the association.

RESULTS

Asthmatic children had a higher risk of also having ADHD [odds ratio (OR) 1.53, 95% confidence interval (CI): 1.16-2.02]. The association was not restricted to either of the two dimensions of ADHD. The magnitude of the association increased with asthma severity (OR 2.84, 95% CI: 1.86-4.35) for ≥ 4 asthma attacks in the last 12 months and was not affected by asthma treatment. The CTCTs possibly indicate that the genetic component in overlap of the disorders is weak.

CONCLUSIONS AND CLINICAL RELEVANCE

Childhood asthma, especially severe asthma, is associated with ADHD. Asthma medication seems not to increase the risk of ADHD. Clinicians should be aware of the potential of ADHD in asthma. Optimal asthma care needs to be integrated with effective evaluation and treatment of ADHD in children with co-existing disorders.

Individual maternal and child exposure to antibiotics in hospital - a national population-based validation study

AIM

Exposure to antibiotics in early life may affect future health. Most antibiotics are prescribed in outpatient care, but inpatient exposure is also important. We estimated how specific diagnoses in hospitals corresponded to individual antibiotic exposure.

METHODS

All pregnant women and children from birth to 5 years of age with infectious diseases and common inpatient diagnoses between July 2005 and November 2011 were identified from the Swedish National Patient Register. Random samples of individuals from predefined groups were drawn, and medical records received from the clinics were manually reviewed for antibiotics.

RESULTS

Medical records for 4319 hospital visits were requested and 3797 (88%) were received. A quarter (25%) of children diagnosed as premature had received antibiotics, and in children from one to 5 years of age, diagnoses associated with bacterial infections were more commonly treated with antibiotics (62.4-90.6%) than those associated with viruses (6.3-22.2%). Pregnant women who had undergone a Caesarean section were more likely to be treated with antibiotics than those who had had a vaginal delivery (40.1% versus 11.1%).

CONCLUSION

This study defines the proportion of new mothers and young children who received individual antibiotic treatment for specific inpatient diagnoses in Sweden and provides a useful basis for future studies focusing on antibiotic use.

The impact of birth mode of delivery on childhood asthma and allergic diseases--a sibling study

BACKGROUND

Caesarean section (CS) has been reported to increase the risk of asthma in offspring. This may be due to that infants delivered by CS are unexposed to vaginal flora, according to the 'hygiene hypothesis'.

OBJECTIVE

Our aim was to investigate if CS increases risk of childhood asthma, and if the risk increase remains after adjustment for familial confounding using sibling design.

METHODS

A register-based cohort study with 87 500 Swedish sibling pairs was undertaken. Asthma outcome variables were collected from national health registers as diagnosis or asthma medication (ICD-10 J45-J46; ATC code R03) during the 10th or 13th year of life (year of follow-up). Mode of delivery and confounders were retrieved from the Medical Birth Register. The data were analysed both as a cohort and with sibling control analysis which adjusts for unmeasured familial confounding.

RESULTS

In the cohort analyses, there was an increased risk of asthma medication and asthma diagnosis during year of follow-up in children born with CS (adjusted ORs, 95% CI 1.13, 1.04-1.24 and 1.10, 1.03-1.18 respectively). When separating between emergency and elective CS the effect on asthma medication remained for emergency CS, but not for elective CS, while both groups had significant effects on asthma diagnosis compared with vaginal delivery. In sibling control analyses, the effect of elective CS on asthma disappeared, while similar but non-significant ORs of medication were obtained for emergency CS.

CONCLUSIONS AND CLINICAL RELEVANCE

An increased risk of asthma medication in the group born by emergency CS, but not elective, suggests that there is no causal effect due to vaginal microflora. A more probable explanation should be sought in the indications for emergency CS.

Familial influence and childhood trauma in female alcoholism

BACKGROUND

To assess the role of genetic and environmental factors in female alcoholism using a large population-based twin sample, taking into account possible differences between early and late onset disease subtype.

METHOD

Twins aged 20-47 years from the Swedish Twin Registry (n=24 119) answered questions to establish lifetime alcohol use disorders. Subjects with alcoholism were classified for subtype. Structural equation modeling was used to quantify the proportion of phenotypic variance due to genetic and environmental factors and test whether heritability in women differed from that in men. The association between childhood trauma and alcoholism was then examined in females, controlling for background familial factors.

RESULTS

Lifetime prevalence of alcohol dependence was 4.9% in women and 8.6% in men. Overall, heritability for alcohol dependence was 55%, and did not differ significantly between men and women, although women had a significantly greater heritability for late onset (type I). Childhood physical trauma and sexual abuse had a stronger association with early onset compared to late onset alcoholism [odds ratio (OR) 2.54, 95% confidence interval (CI) 1.53-3.88 and OR 2.29, 95% CI 1.38-3.79 respectively]. Co-twin analysis indicated that familial factors largely accounted for the influence of physical trauma whereas the association with childhood sexual abuse reflected both familial and specific effects.

CONCLUSIONS

Heritability of alcoholism in women is similar to that in men. Early onset alcoholism is strongly association with childhood trauma, which seems to be both a marker of familial background factors and a specific individual risk factor per se.

Antibiotics and asthma medication in a large register-based cohort study - confounding, cause and effect

BACKGROUND

An association between asthma and antibiotic usage has been demonstrated, and the issue of reverse causation and confounding by indication is much debated.

OBJECTIVE

Our aim was to study the association between different classes of antibiotics and prescription of asthma medication in a register-based cohort of all Swedish children, born between July 2005 and June 2009, ever treated with antibiotics.

METHODS

Data on dispensed prescriptions of antibiotics (ATC-codes J01) and asthma medication (ATC-codes R03A-D) were requested from the Prescribed Drug Register. The association between dispensed prescriptions of different classes of antibiotics and asthma medication was analysed with Cox regression and a descriptive sequence symmetry analysis.

RESULTS

In total, 211 192 children had received prescriptions of antibiotics. There was a strong association between prescription of antibiotics and prescription of asthma medication. The hazard ratios (HRs) for asthma medication associated with prescription of amoxicillin, penicillin, cephalosporin and macrolides (Gram-positive infections) were stronger than HRs associated with prescription of sulphonamides, trimethoprim and quinolones (urinary tract infections) and flucloxacillin (skin and soft tissue infections), e.g. first year HR = 2.27 (95% confidence intervals 2.17-2.37) as compared with HR = 1.04 (0.78-1.40). The HR associated with broad spectrum antibiotics was significantly higher than the narrow spectrum.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data suggest that the association between antibiotics and asthma is subject to either reverse causation or confounding by indication due to respiratory tract infections. This implies that careful consideration is required as to whether or not symptoms from the respiratory tract in early childhood should be treated with antibiotics or asthma medication.

Association between childhood asthma and ADHD symptoms in adolescence--a prospective population-based twin study

BACKGROUND

Cross-sectional studies report a relationship between childhood asthma and attention-deficit hyperactivity disorder (ADHD) symptoms, but the mechanisms are yet unclear. Our objective was to investigate the longitudinal link between childhood asthma and the two dimensions of ADHD (hyperactivity-impulsivity, HI, and inattention, IN) in adolescence. We also aimed to explore the genetic and environmental contributions and the impact of asthma medication.

METHODS

Data on asthma, HI and IN, birth weight, socioeconomic status, zygosity, and medication were collected from the Swedish Medical Birth Register and through parental questionnaires at ages 8-9 and 13-14 years on 1480 Swedish twin pairs born 1985-1986. The association between asthma at age 8-9 and ADHD symptoms at age 13-14 was assessed with generalized estimating equations, and twin analyses to assess the genetic or environmental determinants were performed.

RESULTS

Children with asthma at age 8-9 had an almost twofold increased risk of having one or more symptom of HI (OR 1.88, 95% CI 1.18-3.00) and a more than twofold increased risk to have three symptoms or more of HI (OR 2.73, 95% CI 1.49-5.00) at age 13-14, independent of asthma medication. For IN, no significant relationship was seen. Results from twin modeling indicate that 68% of the phenotypic correlation between asthma and HI (r=0.23, 0.04-0.37) was because of genetic influences.

CONCLUSIONS

Our findings suggest that childhood asthma is associated with subsequent development of HI in early adolescence, which could be partly explained by genetic influences. Early strategies to identify children at risk may reduce burden of the disease in adolescence.

Endometriosis as a prognostic factor for cancer survival

Studies have shown an increased risk of malignancies in women with endometriosis. Little is known about the impact of endometriosis on cancer survival. We investigated whether the survival after a diagnosis of a malignancy differs in women with a previously diagnosed endometriosis compared to other women. Women with a first time diagnosis of a malignancy in 1969-2005, were identified using the National Swedish Cancer Register (NSCR). By use of the National Swedish Patient Register (NSPR) we identified all women with a diagnosis of endometriosis during the same period and linked these patients with the data from the NSCR. The cohort comprised 4,278 women with endometriosis and a malignancy, and 41,831 randomly selected matched women without endometriosis. Cox regression was used for all calculations to obtain crude and adjusted cause specific mortality rates, measured as hazard ratios (HR) with 95% confidence intervals (CI). A total of 46,109 women entered the study. There was a statistically significant better survival for women with endometriosis for all malignancies combined (HR=0.92) and for breast cancer (HR=0.86) and ovarian cancer (HR=0.81) specifically. For breast cancer the survival enhancing effect in women with endometriosis decreased with increasing parity. There was poorer survival in malignant melanoma for women with endometriosis (HR=1.52). The survival in a malignancy is better in women with a previously diagnosed endometriosis compared to women without endometriosis especially for breast and ovarian cancers. The prognosis of malignant melanoma is poorer in women with endometriosis.

Impaired fetal growth decreases the risk of childhood atopic eczema: a Swedish twin study

BACKGROUND

Studies have found associations between birth weight and risk of atopic eczema or allergic rhinitis (AR), although this could be due to confounding.

OBJECTIVE

We sought to evaluate associations between fetal growth and the risk of atopic eczema or AR in childhood, controlling for gestational age (GA), shared (familial) environmental and genetic factors.

METHODS

Data on atopic eczema, AR, birth characteristics and confounders were collected from registers and telephone interviews with the parents of 9- and 12-year-old twins. Firstly, cohort analyses on all twins (eczema n=10 132 and AR n=10 896) were performed. Secondly, to control for genetic and shared environment, co-twin-control analyses were performed in twin pairs discordant for atopic eczema (n=480) and AR (n=332).

RESULTS

The rate of atopic eczema increased with birth weight, from 12.6% in twin children <2000 g to 17.3% in children >or=3500 g. The rate of AR varied between 7.8% and 8.8%. In the cohort analyses, the odds ratio (OR) for atopic eczema was 1.62 (95% CI: 1.27-2.06) for 500 g increase in birth weight and 1.00 (95% CI: 0.75-1.33) for AR. In co-twin-control analyses on atopic eczema, OR was 3.93 (95% CI: 1.55-9.98) for 500 g increase in birth weight, with no significant difference between monozygotic and dizygotic twins (P=0.84).

CONCLUSIONS

We found a positive association between fetal growth and childhood atopic eczema, but not AR, independent of GA, shared environmental and genetic factors. This indicates fetal growth affects the immune system, and supports further studies on early mechanisms.

Influence of hysterectomy on fistula formation in women with diverticulitis

Background

Diverticulitis is a risk factor for fistula formation but little is known about the influence of hysterectomy in this association. A population-based nationwide matched cohort study was performed to determine the risk of fistula formation in hysterectomized women with, and without, diverticulitis.

Methods

Women who had a hysterectomy between 1973 and 2003, and a matched control cohort, were identified from the Swedish Inpatient Register. Incidence of diverticulitis and fistula surgery was determined by cross-linkage to the Register, and risk was estimated using a Cox regression model.

Results

In a cohort of 168 563 hysterectomized and 614 682 non-hysterectomized women (mean follow-up 11·0 and 11·5 years respectively), there were 14 051 cases of diverticulitis and 851 fistulas. Compared with women who had neither hysterectomy nor diverticulitis, the risk of fistula surgery increased fourfold in hysterectomized women without diverticulitis (hazard ratio (HR) 4·0 (95 per cent confidence interval (c.i.) 3·5 to 4·7)), sevenfold in non-hysterectomized women with diverticulitis (HR 7·6 (4·8 to 12·1)) and 25-fold in hysterectomized women with diverticulitis (HR 25·2 (15·5 to 41·2)).

Conclusion

Diverticulitis, and to a lesser extent hysterectomy, is strongly associated with the risk of fistula formation. Hysterectomized women with diverticulitis have the highest risk of developing surgically managed fistula.

5-year followup of a randomized prospective study comparing mitomycin C and bacillus Calmette-Guerin in patients with superficial bladder carcinoma. Swedish-Norwegian Bladder Cancer Study Group

PURPOSE

We report the 5-year followup of a randomized comparison of mitomycin C and bacillus Calmette-Guerin (BCG) in patients with superficial bladder carcinoma. Recurrence, progression and survival rates, crossover results, prognostic factors and long-term side effects were analyzed.

MATERIALS AND METHODS

A total of 261 patients were enrolled in the study, and the inclusion criteria were primary Tis, dysplasia G2, T1 G3 and multiple recurrent Ta/T1 G1-2 disease. Intravesical instillations of 40 mg. mitomycin C and 120 mg. Pasteur BCG, Danish strain 1331, were given for 2 years.

RESULTS

After a median followup of 64 months 101 of the 250 evaluable patients (42%) were disease-free. A significant difference was noted in disease-free survival with BCG (p = 0.04), which was most pronounced for stage Tis disease. No difference in tumor progression, or crude or corrected survival was found between the 2 arms. Crossover treatment was successful in 39% of patients with second line BCG and 19% with second line mitomycin C. Independent risk factors for progression were initial p53 status and stage. Only the completion of treatment was predictive of outcome for patients treated with BCG. Bladder shrinkage occurred in 2.4% of patients.

CONCLUSIONS

Therapy with BCG was superior to mitomycin C for recurrence prophylaxis but no difference was found for progression and survival.

A randomized prospective study comparing long-term intravesical instillations of mitomycin C and bacillus Calmette-Guerin in patients with superficial bladder carcinoma

PURPOSE

We compared the efficacy and toxicity of long-term mitomycin C versus bacillus Calmette-Guerin (BCG) instillation in patients at high risk for recurrence and progression of superficial bladder carcinoma.

MATERIALS AND METHODS

Our randomized comparison study included 261 patients with primary dysplasia, or stage Tis, stage T1, grade 3 and multiple recurrent stage Ta/T1, grade 1 or 2 disease. Mitomycin C (40 mg.) or Pasteur strain BCG (120 mg.) was instilled weekly for 6 weeks, then monthly for up to 1 year and every 3 months during year 2.

RESULTS

After a median followup of 39 months 49% of the patients given BCG and 34% given mitomycin C were disease-free (p < 0.03), compared to 48 and 35%, respectively, of those with stage Ta or T1 disease, and 54 and 33%, respectively, of those with dysplasia or stage Tis tumor. Tumor progressed in 13% of patients, with no statistically significant difference observed regarding progression between the mitomycin C and BCG groups. Side effects were more common after BCG instillation, with 5 cases of severe side effects compared to 1 in the mitomycin C group. Treatment was stopped due to toxicity in 10% of the patients.

CONCLUSIONS

The majority of patients tolerated long-term intravesical therapy well. BCG instillation was hampered by more frequent side effects. BCG was superior regarding recurrence prophylaxis, since patients given BCG had fewer recurrences and a significantly longer time to treatment failure compared to those treated with mitomycin C. No statistically significant difference was observed regarding progression.

Modal DNA values and estramustine-binding protein (EMBP) as prognostic markers in prostatic cancer

In this study, we have investigated the model DNA values and the expression of estramustine-binding protein (EMBP) in formalin-fixed and paraffin-embedded TUR specimens from 76 untreated patients with prostatic cancer. In addition, specimens from 13 patients were analyzed for tumour EMBP expression only. Ploidy was measured as diploid, tetraploid and non-tetraploid aneuploid or aneuploid in the near-diploid region. All patients had been referred during 1978-1981, and were subjected to TUR due to urinary obstruction. Survival data were obtained for all patients through March 1988. Statistical analyses were performed using a Cox's regression model with respect to survival and cause specific survival and correlated to the DNA pattern and the expression of EMBP. The existence of a near-diploid aneuploid cell population as well as poor differentiation grade were both statistically significantly correlated with poor survival. Near-diploid aneuploid cell lines were seen in 9/76 (12%) of the patients and were also seen in well differentiated cancers (4/17). The expression of EMBP was most abundant in the moderately differentiated cancers. However, all prostatic cancer specimens investigated were positive for the antigen. Patients with poorly differentiated carcinomas and high EMBP expression showed a tendency towards better prognosis than those with poorly differentiated carcinomas and low EMBP expression. The present patient material was, however, too small to show a statistically significant correlation between EMBP and survival.