Validation of Photoplethysmography Using a Mobile Phone Application for the Assessment of Heart Rate Variability in the Context of Heart Rate Variability-Biofeedback.

OBJECTIVE: Heart rate variability-biofeedback (HRV-BF) is an effective intervention to reduce stress and anxiety and requires accurate measures of real-time HRV. HRV can be measured through photoplethysmography (PPG) using the camera of a mobile phone. No studies have directly compared HRV-BF supported through PPG against classical electrocardiogram (ECG). The current study aimed to validate PPG HRV measurements during HRV-BF against ECG. METHODS: Fifty-seven healthy participants (70% women) with a mean (standard deviation) age of 26.70 (9.86) years received HRV-BF in the laboratory. Participants filled out questionnaires and performed five times a 5-minute diaphragmatic breathing exercise at different paces (range, ~6.5 to ~4.5 breaths/min). Four HRV indices obtained through PPG, using the Happitech software development kit, and ECG, using the validated NeXus apparatus, were calculated and compared: RMSSD, pNN50, LFpower, and HFpower. Resonance frequency (i.e., optimal breathing pace) was also compared between methods. RESULTS: All intraclass correlation coefficient values of the five different breathing paces were "near perfect" (>0.90) for all HRV indices: lnRMSSD, lnpNN50, lnLFpower, and lnHFpower. All Bland-Altman analyses (with just three incidental exceptions) showed good interchangeability of PPG- and ECG-derived HRV indices. No systematic evidence for proportional bias was found for any of the HRV indices. In addition, correspondence in resonance frequency detection was good with 76.6% agreement between PPG and ECG. CONCLUSIONS: PPG is a potentially reliable and valid method for the assessment of HRV. PPG is a promising replacement of ECG assessment to measure resonance frequency during HRV-BF.

Socioeconomic inequalities in psychosocial problems of children: mediating role of maternal depressive symptoms.

Background: Socioeconomically disadvantaged children often have psychosocial problems. This study examined the mediating role of maternal depressive symptoms during pregnancy, infancy and early childhood in the association between maternal education, as indicator of socioeconomic status (SES), and child's psychosocial problems. Methods: Included were 3410 children from the Amsterdam Born Children and their Development (ABCD) study. To assess the child's psychosocial problems at age 5-6 years, mothers and teachers completed the Strengths and Difficulties Questionnaire (SDQ). Maternal depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale and the Depressive Anxiety and Stress Scale 21. Mediation analysis was performed to calculate the direct effect of maternal education on SDQ score and indirect effects through maternal depressive symptoms. Results: The mean mother-reported SDQ total score was significantly higher (P < 0.001) for children of low-educated mothers (6.74 ± 4.41) compared with children of highly educated mothers (4.47 ± 3.73). Levels of maternal depressive symptoms were also higher in low-educated mothers during pregnancy, infancy and early childhood. Maternal depressive symptoms explained 27.5% of the association between maternal education and mother-reported SDQ scores and 22.9% for combined mother/teacher SDQ scores. Maternal depressive symptoms during pregnancy had the strongest indirect effect. Conclusion: Maternal depressive symptoms during pregnancy mediate the association between low maternal education and child's psychosocial problems. Early recognition and treatment of maternal depressive symptoms is important to prevent psychosocial problems in children, especially in those with low education.

Recent cannabis use among adolescent and young adult immigrants in the Netherlands--the roles of acculturation strategy and linguistic acculturation.

BACKGROUND: The present study examined the relation between two different acculturation measures (i.e., linguistic acculturation and the acculturation strategies integration, separation and marginalization) and past year cannabis use. Additionally, we studied the mediating role of affiliation with cannabis-using peers. METHOD: Data were utilized from i4culture, a Dutch study on immigrant adolescents and young adults aged 15-24 years. Participants belonged to the five largest immigrant populations in the Netherlands, living in or around the four major Dutch cities: Amsterdam, the Hague, Rotterdam, and Utrecht. In total, 771 adolescents and young adults (mean age 19.29, SD=2.61, 53.8% female) from Surinamese (n=210, 27.2%), Moroccan (n=209, 27.1%), Turkish (n=110, 14.3%), Antillean (n=109, 14.1%), and Asian (n=133, 17.3%) backgrounds participated. With questionnaires, past year cannabis use, acculturation strategy, linguistic acculturation, and affiliation with cannabis-using peers were assessed. RESULTS: Using logistic regression analyses, we found no relation between acculturation strategy and past year cannabis use (OR=1.25, p=0.38 for separation vs integration and OR=0.86, p=0.50 for marginalization vs integration). Linguistic acculturation was positively related to cannabis use (OR=2.20, p<0.01). Affiliation with cannabis-using peers partly mediated this relation (OR=1.09, p<0.01). CONCLUSIONS: Non-Western immigrant youngsters who speak the host culture's language at home are more likely to use cannabis than youngsters who speak their native language at home. The former group is more likely to affiliate with cannabis-using peers, which partly explains their increased risk of cannabis use.

The association between neurocognitive functioning and smoking in adolescence: the TRAILS study.

OBJECTIVE: This study examines the association between neurocognitive functioning and tobacco smoking in adolescence. METHOD: Data from three measurements of the longitudinal Tracking Adolescents' Individual Lives Survey (TRAILS), a large regional population-based cohort study of Dutch adolescents, were used. The first measurement took place in 2001-2002 (T1) when participants were age 11, with two follow-up measurements (2003-2004 and 2005-2007; T2 and T3, respectively). A total of 1,797 adolescents participated in all three waves. At T1, they performed a selection of tasks from the Amsterdam Neuropsychological Tasks program (De Sonneville, 1999), which enabled the assessment of the main aspects of neurocognitive functioning. Smoking was assessed with a self-report questionnaire at T1, T2, and T3. In the multivariate analyses we controlled for gender, age, socioeconomic status (SES) and baseline speed. RESULTS: Multivariate logistic regression analyses showed that poor sustained attention increased the likelihood that the adolescent would initiate smoking between T1 and T2. Low inhibition of prepotent responses increased the likelihood of smoking initiation between T1 and T3. An increased ability to inhibit biased response tendencies reduced the likelihood of being a daily smoker at T2. Poor sustained attention increased the likelihood of being a daily smoker at T3. CONCLUSION: Poor sustained attention and low inhibition predicted adolescent smoking. However, the proportion of the variance in smoking risk accounted for by these neurocognitive predictors proved to be small. Thus, although neurocognitive functioning is related to adolescent smoking, it seems to explain only a small part of why adolescents initiate and continue smoking.

Do social disadvantage and early family adversity affect the diurnal cortisol rhythm in infants? The Generation R Study.

Dysregulation of diurnal cortisol secretion patterns may explain the link between adversities early in life and later mental health problems. However, few studies have investigated the influence of social disadvantage and family adversity on the hypothalamic-pituitary-adrenal (HPA) axis early in life. In 366 infants aged 12-20 months from the Generation R Study, a population-based cohort from fetal life onwards, parents collected saliva samples from their infant at 5 moments over the course of 1 day. The area under the curve (AUC), the cortisol awakening response (CAR) and the diurnal cortisol slope were calculated as different composite measures of the diurnal cortisol rhythm. Information about social disadvantage and early adversity was collected using prenatal and postnatal questionnaires. We found that older infants showed lower AUC levels; moreover, infants with a positive CAR were significantly older. Both the AUC and the CAR were related to indicators of social disadvantage and early adversity. Infants of low income families, in comparison to high income families, showed higher AUC levels and a positive CAR. Infants of mothers who smoked during pregnancy were also significantly more likely to show a positive CAR. Furthermore, infants of mothers experiencing parenting stress showed higher AUC levels. The results of our study show that effects of social disadvantage and early adversity on the diurnal cortisol rhythm are already observable in infants. This may reflect the influence of early negative life events on early maturation of the HPA axis.

The role of temperament in the relationship between early onset of tobacco and cannabis use: the TRAILS study.

BACKGROUND: While temperamental characteristics have been related to the onset of cannabis use, it is not clear at what point(s) along the trajectory from early onset of tobacco use (EOT) to early onset of cannabis use (EOC) these characteristics exert their impact. This study examined if (1) temperamental characteristics predispose to EOT that on its turn predisposes to EOC, and (2) temperament moderates the importance of EOT on the progression to EOC. METHODS: Data from 1848 (83%) participants in the TRacking Adolescents' Individual Lives Survey (TRAILS), a prospective population study of Dutch adolescents, were analyzed. We used parent-reports on the Early Adolescent Temperament Questionnaire to assess the dimensions of high-intensity pleasure, frustration, effortful control, shyness and fearfulness at age 10-12. EOT and EOC were defined as use at least once before the ages of 12 and 13 years, respectively, assessed by means of self-reports. We performed mediation and moderation analyses in Mplus. RESULTS: High levels of high-intensity pleasure predisposed to entrance in the trajectory from EOT to EOC. Once tobacco use had been initiated at early age, low levels of shyness and high levels of high-intensity pleasure increased the risk of progression to EOC. CONCLUSIONS: Besides a common liability for EOT and EOC based on temperament, the risk of transition from tobacco to cannabis use is modified by temperamental characteristics. Differences in interplay with other risk factors may explain the impact of temperament on distinct points along the substance use trajectory.

Correlates of smoking cessation in a nationally representative sample of U.S. adults.

Persistent cigarette smoking is associated with significant morbidity and mortality. Correlates of difficulty quitting smoking include psychopathology, such as major depressive disorder, and problems with other substances, such as alcoholism. In addition, socio-demographic risk (e.g. poverty) and protective (e.g. living in a region with stringent tobacco laws) influences can modify risk for persistent cigarette smoking. Using data on 17,919 individuals with a lifetime history of smoking 100 or more cigarettes, from a nationally representative U.S. sample, we examine the constellation of risk and protective factors that correlate with smoking cessation (defined as remaining smoke-free in the past 12 months) across four cohorts: young (18-31 years), intermediate-aged (32-43 years), middle-aged (44-60 years) and older (61-99 years) adults. Using survival analyses, we demonstrate that in addition to a history of DSM-IV nicotine dependence, which is negatively associated with smoking cessation, living below the poverty line is also associated with persistent smoking across all age cohorts. Residents over the age of 31 years living on the U.S. West Coast are less likely to be persistent smokers as well. Major depressive disorder is associated with persistent smoking, but interestingly, only in middle-aged and older adults. Alcoholism and a family history of substance use problems are both correlated with persistent smoking but only in older adults. Here, we find evidence for psychopathology that may hinder successful quit attempts during the developmental period when a majority of quit attempts are made (early to mid-40's). However, our analyses also highlight the important benefits of effective tobacco legislation on the U.S. West Coast and urge policy makers to actively consider addressing issues surrounding tobacco taxation and the impact of poverty on tobacco use, in addition to the risks posed by co-occurring psychiatric problems and other substance use disorders.

Health-related quality of life of firefighters and police officers 8.5 years after the air disaster in Amsterdam.

BACKGROUND: In 1992 a cargo aircraft crashed into apartment buildings in Amsterdam. In the troublesome aftermath rumours emerged on potential toxic exposures and health consequences. The aim of this study is to assess the long-term impact of this disaster on the health-related quality of life (HRQoL) of professional assistance workers. METHODS: Historic cohort study, using questionnaires to assess occupational disaster exposure, HRQoL (SF36), and background variables, at on average 8.5 years post-disaster. Participating were the exposed professional firefighters (n = 334) and police officers (n = 834) who reported disaster-related task(s), and their non-exposed colleagues who did not report such tasks (n = 194, and n = 634, respectively). RESULTS: Multivariate logistic regression analysis showed that exposed workers reported a significantly lower physical HRQoL and vitality than non-exposed workers. Exposed police officers also reported a lower mental HRQoL. Among exposed workers, a lower HRQoL was reported significantly more often by workers who had a close one affected by the disaster; by firefighters who rescued people, cleaned-up, or witnessed the immediate disaster scene; and by police officers who supported the injured. Exposed police officers who perceived the disaster as 'not bad' reported a lower HRQoL less often than those to whom it was 'the worst ever'. CONCLUSIONS: This study demonstrates that professional disaster assistance workers are at risk for a lower HRQoL, even after years.