Time-of-day effects in arousal: disrupted diurnal cortisol profiles in children with ADHD

Background: Fluctuations in attention-deficit hyperactivity disorder (ADHD) symptoms related to regulatory deficits in arousal states are themselves characterized by circadian rhythms. Although cortisol is an important circadian arousal-related marker, studies focusing on across-the-day cortisol variations in ADHD are scarce. There is no study with multiple measurements to take into account interday and intraday variability. Methods: Salivary cortisol was sampled five times a day (awakening, 30 min after awakening, noon, 4 p.m., 8 p.m.) across five consecutive days in 33 children with ADHD (22 with and 11 without oppositional defiant disorder; ODD) and 33 class- and sex-matched controls (aged 612). The cortisol awakening response (increase from awakening to 30 min after awakening) and the diurnal cortisol profile (across-the-day variations) were compared for ADHD with ODD (ADHD + ODD) and without ODD (ADHD) subgroups and the control group. Results: The cortisol awakening response was not significantly different between groups. However, longitudinal analyses to evaluate cortisol profiles across the day revealed a significant Group x Time effect (p < .001). More specifically, compared to each other, the ADHD subgroup showed a flatter slope with relative morning hypo-arousal and evening hyperarousal, whereas the ADHD + ODD subgroup showed a steeper slope with relative morning hyperarousal and evening hypo-arousal (p < .001). Conclusions: Findings support time-related arousal disruptions in children with ADHD associated with the presence or absence of ODD comorbidity. We recommend research on cortisol in larger samples for a better understanding of arousal mechanisms involved in ADHD not only with and without ODD but also with other comorbidities which may have implications for timing of arousal-based treatments

Voedingsopties voor zuigelingen van hiv-positieve moeders in subsaharisch Afrika : richtlijnen en praktijk

Hiv-infectie vormt een majeur gezondheidsprobleem in subsaharisch Afrika. Wereldwijd zijn er naar schatting 2,5 miljoen hiv-positieve kinderen, van wie 90% in subsaharisch Afrika leeft. Kinderen worden voornamelijk besmet via moeder-kindtransmissie, met borstvoeding als een belangrijke factor. Het geven van borstvoeding is in subsaharisch Afrika de norm; economische, infrastructurele, socioculturele en maatschappelijke factoren spelen hier een rol. Vaak geeft men gemengde voeding, bestaande uit borstvoeding in combinatie met fles- en/of andere voeding. Wanneer hiv-positieve moeders hun kind tijdens de eerste 6 levensmaanden uitsluitend borstvoeding geven, is dit een manier om overdracht van de hiv-besmetting van de moeder op het kind te beperken. Dit wordt aangeraden wanneer flesvoeding geen aanvaardbaar, realiseerbaar, betaalbaar, duurzaam of veilig alternatief vormt. Studies in subsaharisch Afrika tonen aan dat het geven van borstvoeding, in vergelijking met enkel flesvoeding, zorgt voor minder ziekte bij het kind, en dat het risico op kindersterfte verlaagt. Uitsluitend borstvoeding geven, verlaagt het transmissierisico van moeder naar kind in vergelijking met het toedienen van gemengde voeding. Het geven van borstvoeding heeft geen negatieve gevolgen voor de gezondheid van de hiv-positieve moeder. De praktische toepassing van de richtlijnen kan enkel binnen een structuur waar diagnostiek, informatieoverdracht, opvolging en ondersteuning voorhanden zijn. Vrouwen in subsaharisch Afrika zouden zo een geïnformeerde voedingskeuze kunnen maken.HIV infection constitutes a major health problem in sub-Saharan Africa. Worldwide it is estimated that 2.5 million children live with HIV, of whom 90% reside in sub-Saharan Africa. Children become mainly infected through a mother-to-child transmission, and when infants are breastfed the infection risk is high. Breastfeeding is a common practice in sub-Saharan Africa, being determined by economic, infrastructural, cultural and social factors. Most often “breastfeeding” implies mixed feeding, consisting of breast milk combined with other food or fluids. Exclusive breastfeeding by HIV-positive mothers during the first six months after birth, may constitute an important strategy to reduce mother-to-child transmission. It remains recommended unless replacement feeding is acceptable, feasible, affordable, sustainable and safe. The results of studies in sub-Saharan Africa reveal that breastfeeding reduces infant morbidity and mortality when compared to exclusive replacement feeding. Compared with mixed feeding, exclusive breastfeeding grants a lower risk of HIV transmission. Breastfeeding is also not associated with higher maternal morbidity or mortality, nor with an increase of HIV disease progression. Implementation of these guidelines will only be possible once the necessary means for early diagnosis of HIV in pregnant women as well as their, intensive counselling, follow-up and support become available. This may allow women in sub-Saharan Africa to make an informed, although often limited, choice on feeding practices

Diurnal variations in arousal: a naturalistic heart rate study in children with ADHD

Previous studies suggest an altered circadian regulation of arousal in children with attention-deficit hyperactivity disorder (ADHD) as measured by activity, circadian preference, and sleep-wake patterns. Although heart rate is an important measure to evaluate arousal profiles, to date it is unknown whether 24-h heart rate patterns differentiate between children with and without ADHD. In this study, 24-h heart rate data were collected in 30 non-medicated children with ADHD (aged 6-11) and 30 sex-, class-, and age-matched normal controls in their naturalistic home and school setting, during 5 days. Simultaneously, 24-h activity patterns were registered. Confounding effects of demographic variables (e.g., age, sex, BMI, pubertal stage) and comorbid internalizing and externalizing problems on heart rate levels were additionally assessed. Longitudinal analysis showed that heart rate levels were overall higher in the ADHD group (p < 0.01)-with the largest effects during afternoon and night-in a model controlling for age. Other factors did not significantly contribute to variations in heart rate levels. Compared to controls, children with ADHD showed higher activity levels during daytime (especially early afternoon), but not during nighttime (p < 0.05). Post hoc analyses showed that environmental effects might influence daytime variations. Findings suggest an autonomic imbalance in children with ADHD as compared to controls, with higher heart rate levels in the ADHD group. Nighttime tachycardia in this group could not be explained by nighttime activity levels or comorbid externalizing/internalizing problems. Further research on autonomic functioning in ADHD is recommended because of the major impact of higher resting heart rate on health outcomes

The impact of idle time in the classroom: differential effects on children with ADHD

Objective: Studies have identified an exacerbation of ADHD deficits under specific laboratory conditions. Less is known about the significance of such contextual factors in relation to everyday functioning in naturalistic settings. Method: This study investigated the differential impact of classroom idle timeperiods when students are not actively engaged or waiting for a taskon the behavior of 31 children with ADHD (25 boys and 6 girls; aged 6-12 years) and 31 sex- and age-matched typically developing classmates, who were simultaneously observed in their normal classroom during two school days. Results: Both groups experienced the same amount of idle time (12% of the time). During idle time, however, levels of hyperactivity and noisiness increased significantly more in children with ADHD than in their classmates (p < .05). Conclusion: Findings highlight the differential susceptibility of ADHD children to classroom idle time. Classroom interventions might consider targeting specifically these periods to reduce disruptive behavior in these children