Biological Rhythm Disruption Associated with Obesity in School Children

Children with obesity have poorer circadian health as assessed by a global circadian health score

BACKGROUND

Circadian health refers to individuals' well-being and balance in terms of their circadian rhythm. It is influenced by external cues. In adults, a close relationship between circadian-related alterations and obesity has been described. However, studies in children are scarce, and circadian health and its association with obesity have not been evaluated globally. We aimed to assess whether circadian health differed between children with and without obesity as determined by a global circadian score (GCS) in a school-age population.

METHODS

Four hundred and thirty-two children (7-12 years) were recruited in Spain. Non-invasive tools were used to calculate the GCS: (1) 7-day rhythm of wrist temperature (T), activity (A), position (P), an integrative variable that combines T, A, and P (TAP); (2) cortisol; and (3) 7-day food and sleep records. Body mass index, body fat percentage, waist circumference (WC), melatonin concentration, and cardiometabolic marker levels were determined.

RESULTS

Circadian health, as assessed by the GCS, differed among children with obesity, overweight, and normal weight, with poorer circadian health among children with obesity. Children with obesity and abdominal obesity had 3.54 and 2.39 greater odds of having poor circadian health, respectively, than did those with normal weight or low WC. The percentage of rhythmicity, a marker of the robustness of the TAP rhythm, and the amplitude, both components of the GCS, decreased with increasing obesity. Different lifestyle behaviors were involved in the association between circadian health and obesity, particularly protein intake (P = 0.024), physical activity level (P = 0.076) and chronotype (P = 0.029).

CONCLUSIONS

The GCS can capture the relationship between circadian health and obesity in school-age children. Protein intake, physical activity level, and chronotype were involved in this association. Early intervention based on improving circadian health may help to prevent childhood obesity.

Moderating effects of smoking and drinking on the relationship between biological rhythm and psychological health and gender differences among adolescents

OBJECTIVES

To determine whether smoking and drinking moderate the correlation between biological rhythm and mental health and the role of gender differences in these moderating effects.

METHODS

Adolescents from three cities, all twelve middle schools (N = 7,986), named Shenzhen, Nanchang and Shenyang in China, were asked to complete a standardized questionnaire including the details of biological rhythm, psychological health, and the status of smoking and drinking. The PROCESS program was used to analyze whether smoking and drinking moderated the relationship between biological rhythm and psychological health.

RESULTS

The analyses revealed poorer psychological health and greater likelihood of smoking and drinking in participants with higher scores for biological rhythm disorder (P < 0.001). Specifically, smoking and drinking accelerated the relationship between biological rhythm and psychological health in the total sample (B = 0.05, P < 0.05; B = 0.06, P < 0.001) and only the subgroup of girls (B = 0.09, P < 0.05; B = 0.12, P < 0.001), respectively.

CONCLUSIONS

As the findings suggest, attention should be given to smoking, drinking and gender-specific approaches employed to alleviate the psychological disorders of adolescents with biological rhythm disorders.

Continuous body temperature as a window into adolescent development

Continuous body temperature is a rich source of information on hormonal status, biological rhythms, and metabolism, all of which undergo stereotyped change across adolescence. Due to the direct actions of these dynamic systems on body temperature regulation, continuous temperature may be uniquely suited to monitoring adolescent development and the impacts of exogenous reproductive hormones or peptides (e.g., hormonal contraception, puberty blockers, gender affirming hormone treatment). This mini-review outlines how traditional methods for monitoring the timing and tempo of puberty may be augmented by markers derived from continuous body temperature. These features may provide greater temporal precision, scalability, and reduce reliance on self-report, particularly in females. Continuous body temperature data can now be gathered with ease across a variety of wearable form factors, providing the opportunity to develop tools that aid in individual, parental, clinical, and researcher awareness and education.

Adolescent Development of Biological Rhythms in Female Rats: Estradiol Dependence and Effects of Combined Contraceptives

Adolescence is a period of continuous development, including the maturation of endogenous rhythms across systems and timescales. Although, these dynamic changes are well-recognized, their continuous structure and hormonal dependence have not been systematically characterized. Given the well-established link between core body temperature (CBT) and reproductive hormones in adults, we hypothesized that high-resolution CBT can be applied to passively monitor pubertal development and disruption with high fidelity. To examine this possibility, we used signal processing to investigate the trajectory of CBT rhythms at the within-day (ultradian), daily (circadian), and ovulatory timescales, their dependence on estradiol (E2), and the effects of hormonal contraceptives. Puberty onset was marked by a rise in fecal estradiol (fE2), followed by an elevation in CBT and circadian power. This time period marked the commencement of 4-day rhythmicity in fE2, CBT, and ultradian power marking the onset of the estrous cycle. The rise in circadian amplitude was accelerated by E2 treatment, indicating a role for this hormone in rhythmic development. Contraceptive administration in later adolescence reduced CBT and circadian power and resulted in disruption to 4-day cycles that persisted after discontinuation. Our data reveal with precise temporal resolution how biological rhythms change across adolescence and demonstrate a role for E2 in the emergence and preservation of multiscale rhythmicity. These findings also demonstrate how hormones delivered exogenously in a non-rhythmic pattern can disrupt rhythmic development. These data lay the groundwork for a future in which temperature metrics provide an inexpensive, convenient method for monitoring pubertal maturation and support the development of hormone therapies that better mimic and support human chronobiology.

Prevalence of overweight and obesity in Brazilian children and adolescents: a systematic review

abstract It is important to know about overweight and obesity situation of Brazilian children and adolescents. The present study aims to update scientific production, through a systematic review, on the prevalence and factors associated with overweight and obesity in Brazilian children and adolescents. Nine databases were verified, and 1,316 references were examined from 2018 to 2019. The electronic search was conducted by three independent researchers. All review steps followed a strategy based on PRISMA. 40 studies were included in this systematic review. Most studies use the World Health Organization classification criteria. The prevalence of overweight in Brazilian children and adolescents varies from 8.8% to 22.2% (boys: 6.2% to 21%; girls: 6.9% to 27.6%). The prevalence of obesity varied from 3.8% to 24% (boys: 2.4% to 28.9%; girls: 1.6% to 19.4%). It was observed that the socioeconomic factors (sex, skin color, economic level, region, mother's educational level, living in a rented house and without access to the internet), hereditary/genetic (family history of dyslipidemia and overweight and rs9939609 genotype) and behavioral (physical activity, screen time, eating habits, perceived body weight, health vulnerability, presence of a result close to home, alcoholic beverages, cigarette consumption) were associated with the outcome. It is concluded that the prevalence of overweight and obesity among Brazilian children and adolescents are worrisome and most of the factors associated with the outcomes are subject to change from the adoption of a healthy lifestyle.

Evidence for disruption of diurnal salivary cortisol rhythm in childhood obesity: relationships with anthropometry, puberty and physical activity

Background

The aim of this study was to examine the characteristics of diurnal cortisol rhythm in childhood obesity and its relationships with anthropometry, pubertal stage and physical activity.

Methods

Thirty-five children with obesity (median age: 11.80[interquartile range 10.30, 13.30] and median BMI z-score: 3.21[interquartile range 2.69, 3.71]) and 22 children with normal weight (median age: 10.85[interquartile range 8.98, 12.13] and median BMI z-score: − 0.27[interquartile range − 0.88, 0.35]) were recruited. Saliva samples were collected at 08:00, 16:00 and 23:00 h. Cortisol concentrations at 3 time points, corresponding areas under the curve (AUCs) and diurnal cortisol slope (DCS) were compared between the two groups. Anthropometric measures and pubertal stage were evaluated, and behavioural information was obtained via questionnaires.

Results

Children with obesity displayed significantly lower cortisol_08:00 (median [interquartile range]: 5.79[3.42,7.73] vs. 8.44[5.56,9.59] nmol/L, P = 0.030) and higher cortisol_23:00 (median [interquartile range]: 1.10[0.48,1.46] vs. 0.40[0.21,0.61] nmol/L, P < 0.001) with a flatter DCS (median [interquartile range]: − 0.29[− 0.49, 0.14] vs. -0.52[− 0.63, 0.34] nmol/L/h, P = 0.006) than their normal weight counterparts. The AUC increased with pubertal development (AUC_{08:00–16:00}:P = 0.008; AUC_{08:00–23:00}: P = 0.005). Furthermore, cortisol_08:00 was inversely associated with BMI z-score (β = − 0.247, P = 0.036) and waist-to-height ratio (WHtR) (β = − 0.295, P = 0.027). Cortisol_23:00 was positively associated with BMI z-score (β = 0.490, P<0.001), WHtR (β = 0.485, P<0.001) and fat mass percentage (FM%) (β = 0.464, P<0.001). Absolute values of DCS were inversely associated with BMI z-score (β = − 0.350, P = 0.009), WHtR (β = − 0.384, P = 0.004) and FM% (β = − 0.322, P = 0.019). In multivariate analyses adjusted for pubertal stage and BMI z-score, Cortisol_08:00, AUC_{08:00–16:00} and absolute values of DCS were inversely associated with the relative time spent in moderate to vigorous intensity physical activity (P < 0.05). AUC_{16:00–23:00} was positively associated with relative non-screen sedentary time and negatively associated with sleep (P < 0.05).

Conclusions

The disorder of diurnal salivary cortisol rhythm is associated with childhood obesity, which is also influenced by puberty development and physical activity. Thus, stabilizing circadian cortisol rhythms may be an important approach for childhood obesity.