Revisiting trajectories of BMI in youth : an in‐depth analysis of differences between BMI and other adiposity measures

Objective Body mass index (BMI) is used to identify trajectories of adiposity in youth, but it does not distinguish fat- from fat-free-mass. There are other inexpensive measures of adiposity which might better capture fat-mass in youth The objective of this study is to examine differences between sex-specific trajectories of BMI and other adiposity indicators (subscapular and triceps skinfold thickness, waist circumference, waist-to-height ratio) which may better capture fat-mass in youth. Methods Data come from four cycles of a longitudinal cohort of 1293 students in Montréal, Canada at ages 12, 15, 17 and 24. Group-based trajectory models identified sex-specific adiposity trajectories among participants with data in ≥3 cycles (n = 417 males; n = 445 females). Results There were six trajectory groups in males and females for all five indicators, except for waist circumference (seven) in both sexes and triceps skinfold thickness (four) and waist-to-height ratio (five) in females. Most trajectories indicated linear increases; only the skinfold thickness indicators identified a decreasing trajectory. While all indicators identified a trajectory with high levels of adiposity, they differed in the number and relative size of trajectories pertaining to individuals in lower half of the adiposity distribution. Conclusion BMI is a satisfactory indicator of adiposity in youth if the aim of the trajectory analysis is to identify youth with excess adiposity, a known risk factor for cardiometabolic outcomes in adulthood

Five-year predictors of physical activity decline among adults in low-income communities: a prospective study

BACKGROUND: Obesity in North America is now endemic, and increased understanding of the determinants of physical inactivity is critical. This analysis identified predictors of declines in physical activity over 5 years among adults in low-income, inner-city neighbourhoods. METHODS: Data on leisure time physical activity were collected in telephone interviews in 1992 and 1997 from 765 adults (47% of baseline respondents), as part of the evaluation of a community-based cardiovascular disease risk reduction program. RESULTS: One-third of 527 participants who were physically active at baseline, were inactive in 1997. Predictors of becoming inactive included female sex (OR = 1.63 95% CI (1.09, 2.43)), older age (1.02 (1.01, 1.04)), higher BMI (1.57 (1.03, 2.40)), poor self-rated health (1.39 (1.05, 1.84)), lower self-efficacy for physical activity (1.46 (1.00, 2.14)), and not using a neighborhood facility for physical activity (1.61 (1.02, 2.14)). CONCLUSION: These results highlight the fact that a variety of variables play a role in determining activity level, from demographic variables such as age and sex, to psychosocial and environmental variables. In addition, these results highlight the important role that other health-related variables may play in predicting physical activity level, in particular the observed association between baseline BMI and the increased risk of becoming inactive over time. Lastly, these results demonstrate the need for multi-component interventions in low-income communities, which target a range of issues, from psychosocial factors, to features of the physical environment

Factors Associated with Sustained Exergaming: Longitudinal Investigation.

International audienceBACKGROUND: Exergaming is technology-driven physical activity (PA) which, unlike traditional video game play, requires that participants be physically active to play the game. Exergaming may have potential to increase PA and decrease sedentary behavior in youth, but little is known about sustained exergaming.OBJECTIVE: The objectives of this study were to describe the frequency, correlates, and predictors of sustained exergaming.METHODS: Data were available in AdoQuest (2005-11), a longitudinal investigation of 1843 grade 5 students in Montréal, Canada. This analysis used data from grade 9 (2008-09) and 11 (2010-11). Participants at Time 1 (T1; mean age 14 years, SD 0.8 ) who reported past-week exergaming (n=186, 19.1% of AdoQuest sample) completed mailed self-report questionnaires at Time 2 (T2; mean age 16 years, SD 0.8). Independent sociodemographic, psychological, and behavioral correlates (from T2)/predictors (from T1 or earlier) were identified using multivariable logistic regression.RESULTS: Of 186 exergamers at T1, 81 (44%) reported exergaming at T2. Being female and having higher introjected regulation (ie, a type of PA motivation indicative of internalizing PA as a behavior) were independent correlates. None of the predictors investigated were associated with sustained exergaming.CONCLUSIONS: Almost half of grade 9 exergamers sustained exergaming for 2 years. Exergaming may be a viable approach to help adolescents engage in and sustain PA during adolescence. Sex and PA motivation may be important in the sustainability of exergaming

Maternal psychiatric disorders and risk of preterm birth

To study the effect of maternal psychiatric disorders (depression, anxiety disorder, bipolar disease, schizophrenia, unspecified psychiatric disorder, and comorbid conditions) and odds of preterm birth

A time compositional analysis of the association between movement behaviors and indicators of mental health in young adults

Background Movement behaviors (i.e., physical activity [PA], sedentary behaviors [SB], sleep) relate to mental health. Although movement behaviors are often analyzed as distinct entities, they are in fact highly inter-dependent (e.g., if an individual increases sleep, then PA and/or SB must be reduced) and these dependencies should be accounted for in the analysis. We tested whether perceptions of time spent in movement behaviors (i.e., moderate-to-vigorous intensity PA [MVPA], light physical activity [LPA], SB, and sleep) related to depressive symptoms and self-report mental health in young adults using a compositional analysis. We then estimated change in depressive symptoms with reallocation of time across movement behaviors using compositional time-reallocation models. Methods Data were drawn from the longitudinal NDIT dataset. Complete data were available for 770 young adults (Mage = 20.3, 55% females). Results The proportion of time spent in MVPA relative to other movement behaviors related to depressive symptoms non-significantly and to mental health significantly. Reallocating 15 min from MVPA to SB resulted in a significant (0.46 unit) increase in depressive symptoms, and reallocating 15 min of MVPA to LPA was associated with a (0.57) increase in depressive symptoms. Conclusion These results indicate the importance of relative time spent in each movement behavior to mental health. Further research should examine these associations over time

Effect of maternal chronic disease on obstetric complications in twin pregnancies in a United States cohort

To evaluate the effect of maternal chronic disease on obstetric complications among twin pregnancies

A longitudinal study of change in substance use from before to during the COVID-19 pandemic in young adults

Introduction We assessed change in substance use from before to during the COVID-19 pandemic in young adults and identified factors associated with initiation/increase in use. Methods The sample comprised young adults from a longitudinal investigation of 1294 youth recruited at ages 12-13 (1999-2000) in 10 Montr eal-area high schools. Pre-pandemic data on use of cannabis, alcohol, combustible ciga- rette, e-cigarette and binge drinking were collected at ages 20.4, 24.0 and 30.6. During COVID-19, data were col- lected from December 2020 to June 2021 (age 33.6). We studied the prevalence of any and weekly/daily use from age 20.4 to 33.6. Individual-level change in substance use during the pandemic was estimated as differences in the fre- quency of use from age 30.6 to 33.6 versus from age 24.0 to 30.6. Heterogeneity in the risk of initiated/increased sub- stance use during COVID-19 across sociodemographic subgroups was assessed using modified Poisson regression. Results The prevalence of cannabis use increased from 17.5% to 23.1% from before to during the pandemic; e-ciga- rette use increased from 3.8% to 5.4%. In individual change analyses, the proportion of participants whose substance use did not change ranged from 48.9% (alcohol) to 84.0% (e-cigarettes). The incidence of initiated/increased canna- bis use (22.4%), and quit/decreased alcohol (35.2%) and binge drinking (53.5%) were higher during the pandemic than between ages 24.0 to 30.6. Low education and living alone were associated with higher risks of initiated/ increased use of most substances. Discussion Most participants reported stable patterns in substance use from before to during the COVID-19 pandemic

A prognostic tool to identify adolescents at high risk of becoming daily smokers

<p>Abstract</p> <p>Background</p> <p>The American Academy of Pediatrics advocates that pediatricians should be involved in tobacco counseling and has developed guidelines for counseling. We present a prognostic tool for use by health care practitioners in both clinical and non-clinical settings, to identify adolescents at risk of becoming daily smokers.</p> <p>Methods</p> <p>Data were drawn from the Nicotine Dependence in Teens (NDIT) Study, a prospective investigation of 1293 adolescents, initially aged 12-13 years, recruited in 10 secondary schools in Montreal, Canada in 1999. Questionnaires were administered every three months for five years. The prognostic tool was developed using estimated coefficients from multivariable logistic models. Model overfitting was corrected using bootstrap cross-validation. Goodness-of-fit and predictive ability of the models were assessed by R², the c-statistic, and the Hosmer-Lemeshow test.</p> <p>Results</p> <p>The 1-year and 2-year probability of initiating daily smoking was a joint function of seven individual characteristics: age; ever smoked; ever felt like you needed a cigarette; parent(s) smoke; sibling(s) smoke; friend(s) smoke; and ever drank alcohol. The models were characterized by reasonably good fit and predictive ability. They were transformed into user-friendly tables such that the risk of daily smoking can be easily computed by summing points for responses to each item. The prognostic tool is also available on-line at <url>http://episerve.chumontreal.qc.ca/calculation_risk/daily-risk/daily_smokingadd.php</url>.</p> <p>Conclusions</p> <p>The prognostic tool to identify youth at high risk of daily smoking may eventually be an important component of a comprehensive tobacco control system.</p

Global use of Haemophilus influenzae type b conjugate vaccine.

Haemophilus influenzae type b (Hib) conjugate vaccines have been underutilized globally. We report progress in global use of Hib vaccines included in national immunization schedules. The number of countries using Hib vaccine increased from 89/193 (46%) in 2004 to 158/193 (82%) by the end of 2009. The increase was greatest among low-income countries eligible for financial support from the GAVI Alliance [13/75 (17%) in 2004, 60/72 (83%) by the end of 2009], and can be attributed to various factors. Additional efforts are still needed to increase vaccine adoption in lower middle income countries [20/31 (65%) by the end of 2009]

Physical activity mediates the relationship between outdoor time and mental health

Both spending time outdoors and participating in physical activity improve mental health. Given that the outdoor environment provides an ideal location for physical activity, better understanding of the relationships among time spent outdoors, physical activity and positive mental health is needed to help guide interventions. The aim was to examine if physical activity moderates or mediates the relationship between outdoor time and positive mental health. Two-hundred-forty-two participants (15 ± 1 years old, 59% girls) from New Brunswick, Canada were included in the current analysis. Youth self-reported time spent outdoors and moderate-to-vigorous physical activity (MVPA) three times between October 2016 and June 2017. Data on their mental health were collected in October 2017. Values of outdoor time and MVPA were averaged across the three time points to represent the exposure and mediator variables, respectively. Mental health, dichotomized as flourishing/not flourishing, was the outcome in the mediation analysis. An interaction term tested if the mediation effect depended on outdoor time. Analyses were undertaken in 2019 using the mediation package in R. In univariate analyses, both MVPA (p < 0.001) and outdoor time (p = 0.05) were positive predictors of flourishing mental health. In mediation analyses, a small indirect mediation (OR: 1.02, 95% CI: 1.01–1.04) and no direct (1.00, 0.98–1.05) effect were noted, suggesting that MVPA mediates the effect of outdoor time on positive mental health. This effect did not vary as a function of outdoor time (interaction: 1.00, 0.99–1.01). Physical activity mediates the relationship between outdoor time and positive mental health. Outdoor time could promote positive mental health among youth through increases in physical activity