Stabilizing prevalence trends of eczema, asthma and rhinoconjunctivitis in Dutch schoolchildren (2001-2010).

In contrast to many countries, a decrease in childhood wheeze prevalence was previously reported for the Netherlands. In repeated cross-sectional surveys in 2001, 2005 and 2010, we investigated whether this trend continued, and additionally examined prevalence trends of eczema, asthma and rhinoconjunctivitis among 8- to 11-year-old schoolchildren eligible for a routine physical examination. Overall, ~90% participated (mean age: 8.8 years in 2001 and 10.5 years in 2005 and 2010). Eczema, wheeze and asthma prevalence did not change significantly between 2001 and 2010, but rhinoconjunctivitis prevalence increased from 8.4% in 2001 to 12.3% in both 2005 and 2010 (Ptrend < 0.01). In conclusion, after a decrease in wheeze prevalence among Dutch schoolchildren between 1989 and 2001, no further decrease was observed until 2010. Similarly, the prevalence of eczema and asthma remained stable, but rhinoconjunctivitis prevalence increased between 2001 and 2010. The latter may be an effect of older age and not a true increase over time.

A genetic perspective on the proposed inclusion of cannabis withdrawal in DSM-5.

BACKGROUND: Various studies support the inclusion of cannabis withdrawal in the diagnosis of cannabis use disorder (CUD) in the upcoming DSM-5. The aims of the current study were to (1) estimate the prevalence of DSM-5 cannabis withdrawal (criterion B), (2) estimate the role of genetic and environmental influences on individual differences in cannabis withdrawal and (3) determine the extent to which genetic and environmental influences on cannabis withdrawal overlap with those on DSM-IV-defined abuse/dependence. METHOD: The sample included 2276 lifetime cannabis-using adult Australian twins. Cannabis withdrawal was defined in accordance with criterion B of the proposed DSM-5 revisions. Cannabis abuse/dependence was defined as endorsing one or more DSM-IV criteria of abuse or three or more dependence criteria. The classical twin model was used to estimate the genetic and environmental influences on variation in cannabis withdrawal, along with its covariation with abuse/dependence. RESULTS: Of all the cannabis users, 11.9% met criteria for cannabis withdrawal. Around 50% of between-individual variation in withdrawal could be attributed to additive genetic variation, and the rest of the variation was mostly due to non-shared environmental influences. Importantly, the genetic influences on cannabis withdrawal almost completely (99%) overlapped with those on abuse/dependence. CONCLUSIONS: We have shown that cannabis withdrawal symptoms exist among cannabis users, and that cannabis withdrawal is moderately heritable. Genetic influences on cannabis withdrawal are the same as those affecting abuse/dependence. These results add to the wealth of literature that recommends the addition of cannabis withdrawal to the diagnosis of DSM-5 CUD.

The relationship between cannabis involvement and suicidal thoughts and behaviors.

BACKGROUND: In the present study, we examined the relationship between cannabis involvement and suicidal ideation (SI), plan and attempt, differentiating the latter into planned and unplanned attempt, taking into account other substance involvement and psychopathology. METHODS: We used two community-based twin samples from the Australian Twin Registry, including 9583 individuals (58.5% female, aged between 27 and 40). The Semi-Structured Assessment of the Genetics of Alcoholism (SSAGA) was used to assess cannabis involvement which was categorized into: (0) no cannabis use (reference category); (1) cannabis use only; (2) 1-2 cannabis use disorder symptoms; (3) 3 or more symptoms. Separate multinomial logistic regression analyses were conducted for SI and suicide attempt with or without a plan. Twin analyses examined the genetic overlap between cannabis involvement and SI. RESULTS: All levels of cannabis involvement were related to SI, regardless of duration (odds ratios [ORs]=1.28-2.00, p<0.01). Cannabis use and endorsing ≥3 symptoms were associated with unplanned (SANP; ORs=1.95 and 2.51 respectively, p<0.05), but not planned suicide attempts (p>0.10). Associations persisted even after controlling for other psychiatric disorders and substance involvement. Overlapping genetic (rG=0.45) and environmental (rE=0.21) factors were responsible for the covariance between cannabis involvement and SI. CONCLUSIONS: Cannabis involvement is associated, albeit modestly, with SI and unplanned suicide attempts. Such attempts are difficult to prevent and their association with cannabis use and cannabis use disorder symptoms requires further study, including in different samples and with additional attention to confounders.

Infant immunization and the occurrence of atopic disease in Dutch and German children: a nested case-control study.

Our goal was to assess the role of early childhood vaccination in the occurrence of respiratory symptoms and allergic sensitization in 7-8-year-old Dutch and German children. A nested case-control study was conducted among children participating in a large longitudinal study on respiratory health, to study the relationship between vaccination (bacille Calmette-Guérin (BCG), pertussis, measles/mumps, rubella, and Haemophilus influenza type b (Hib)) and respiratory symptoms and allergic sensitization. Parents of 510 7-8-year-old children with respiratory complaints and an equal number of randomly selected children without respiratory complaints were asked to complete a questionnaire. Blood samples were collected for specific serum IgE analysis. Vaccination status was assessed through the records of the participating Municipal Health Services. No association between vaccination against pertussis, measles, rubella, or Hib and respiratory symptoms or allergic sensitization was found. For sensitization against house dust mite, BCG vaccination resulted in an increased risk (OR, 2.28; 95% CI, 1.05-4.96). Birth order was inversely associated with allergic sensitization, but was not related to respiratory symptoms. We found an association between BCG vaccination and the subsequent risk for sensitization against house dust mite. No evidence was found for an association between vaccination and respiratory symptoms. Earlier reports of an association of birth order with atopic disease were supported by the results of the present study.

The effect of maternal hyperoxia on breathing movements, body movements and rest-activity cycles of low-risk human fetuses.

The effects of maternal hyperoxia on fetal breathing and body movements, and on fetal activity state as reflected in the fetal heart rate pattern, were studied in 20 healthy gravida. Fetal breathing and trunk movements were observed by means of real-time ultrasound scanning, and the fetal heart rate was recorded continuously before, during and after 30 min of maternal oxygen inhalation by mask. Maternal transcutaneous oxygen tension (TcPO2) was measured in 9 subjects. The protocol was also carried out in ten of the gravidas with substitution of compressed air for oxygen. Maternal TcPO2 nearly doubled during oxygen breathing in the subjects in whom this was measured. There were no significant changes in the incidence of fetal breathing or trunk movements, or in the distribution of heart rate patterns, during maternal oxygen breathing. Also, no differences were observed in these variables between the oxygen and compressed-air experiments. We conclude that the normal level of fetal oxygenation does not limit fetal activity in uncomplicated pregnancies.

Predicting transitions in low and high levels of risk behavior from early to middle adolescence: the TRAILS study.

The present study examined the joint development of substance use and externalizing problems in early and middle adolescence. First, it was tested whether the relevant groups found in previous studies i.e., those with an early onset, a late onset, and no onset or low levels of risk behavior could be identified, while using a developmental model of a single, underlying construct of risk behavior. Second, departing from Moffitt's taxonomy of antisocial behavior, it was tested if early, but not late, onset risk behavior is predicted by a problematic risk profile in childhood. Data were used from TRAILS, a population based cohort study, starting at age 11 with two follow-ups at mean ages of 13.6 and 16.3 years. Latent transition analyses demonstrated that, both in early and middle adolescence, a single underlying construct of risk behavior, consisting of two classes (labeled as low and high risk behavior), adequately represented the data. Respondents could be clearly classified into four possible transition patterns from early to middle adolescence, with a transition from high to low being almost non-existent (2.5 %), low to low (39.4 %) and low to high (41.8 %) being the most prevalent, and high to high (16.2 %) substantial. As hypothesized, only the high-high group was characterized by a clear adverse predictor profile in late childhood, while the low-high group was not. This study demonstrates that the development of substance use is correlated with externalizing problems and underscores the theory that etiologies of early and later onset risk behavior are different.

DRD2 and DRD4 in relation to regular alcohol and cannabis use among adolescents: does parenting modify the impact of genetic vulnerability? The TRAILS study.

AIMS: The aims of the present study were to determine the direct effect of DRD2 and DRD4, as well as their interaction with parenting (i.e. rejection, overprotection and emotional warmth), on the development of regular alcohol and cannabis use in 1192 Dutch adolescents from the general population. METHODS: Information was obtained by self-report questionnaires. Perceived rejection, overprotection and emotional warmth were assessed at age 10-12. Regular alcohol and cannabis use were determined at age 15-18 and defined as the consumption of alcohol on 10 or more occasions in the past four weeks, and the use of cannabis on 4 or more occasions in the past four weeks. Models were adjusted for age, sex, parental alcohol or cannabis use, and externalizing behavior. RESULTS: Carrying the A1 allele of the DRD2 TaqIA polymorphism, or the 7 repeat DRD4, was not directly related to regular alcohol or cannabis use. In addition, adolescent carriers of these genetic risk markers were not more susceptible to the influence of less optimal parenting. Main effects for parenting indicated that overprotection increased the risk of regular alcohol use, whereas the risk of cannabis use was enhanced by parental rejection and buffered by emotional warmth. CONCLUSIONS: Our findings do not support an association between DRD2/DRD4 and regular alcohol and cannabis use in adolescents. Given the substance-specific influences of rejection, overprotection and emotional warmth, these parenting factors might be promising candidates for prevention work.