Objectively measured physical activity and sedentary time: cross-sectional and prospective associations with adiposity in the Millennium Cohort Study

Abstract

ObjectiveTo examine whether physical activity (PA) and sedentary time (ST) in primary school-aged children are associated with adiposity at the start of secondary school, and whether these associations differ by sex or ethnic group.DesignNationally representative prospective cohort study.SettingChildren born across the UK, between 2000 and 2002.Participants6497 singleton children.Outcome measuresMeasures of adiposity (body mass index (BMI), fat mass index (FMI) and fat free mass index (FFMI))—obtained at 7 and 11 years.Explanatory measuresTotal daily PA (mean counts per minute (cpm)); minutes of moderate-to-vigorous PA (MVPA); and ST. All assessed at 7 years using accelerometers.ResultsIn cross-sectional analyses, total PA was inversely associated with FMI (3.7% (95% CI 2.7% to 4.7%) reduction per 150 cpm increase), as was MVPA (4.2% (CI 3.2% to 5.2%) reduction per 20 min/day increase). Associations were stronger in black and South Asian ethnic groups. Total PA and MVPA were not associated with FFMI. ST was positively associated with FMI (1.3% (CI 0.2% to 2.3%) increase per 50 min/day increase) and inversely associated with FFMI (0.5% (CI 0.2% to 0.7%) reduction per 50 min/day increase). Longitudinally, MVPA at age 7 years remained inversely associated with FMI at age 11 years (1.5% (CI 0.4% to 2.6%) reduction per 20 min/day increase). No association was found between total PA and ST and any of the later adiposity measures.Conclusions7-year-old children who are more physically active are less likely to be obese at that age and at age 11 years. These associations were particularly evident in children from black or South Asian ethnicity at age 7 years and in boys at age 11 years. Measurements of fat mass provide valuable insights into ethnic differences in associations between adiposity and activity.

The prospective association between objectively measured sedentary time, moderate‐to‐vigorous physical activity and cardiometabolic risk factors in youth: a systematic review and meta‐analysis

“…Two studies found that sedentary time predicted lower BMI and WC , even after adjustment of MVPA. In general, studies examining the prospective associations between sedentary time and adiposity reported no evidence for any association . Activity of at least moderate intensity was inversely associated with BMI and WC .…”

Proportion of children meeting recommendations for 24-hour movement guidelines and associations with adiposity in a 12-country study

“…Isolated adherence to MVPA, screen time and sleep duration recommendations have been associated with lower adiposity indicators in children and adolescents [3, 5–10]. How combinations of these movements behaviors are associated with obesity is largely unknown as few studies have examined the influence of meeting specific movement behavior recommendation combinations and obesity, and only a subset have considered sleep duration as a health-related risk behavior in combined analyses [11–18].…”

Results From Spain’s 2016 Report Card on Physical Activity for Children and Youth

“…In children and adolescents, adiposity, cardiovascular biomarkers, bone health, physical fitness, quality of life, motor skills development, and psychological distress have been associated with physical activity (PA), measured either in terms of minutes dedicated to total, light, moderate, and vigorous intensities [1][2][3][4] or sedentary time. 1,5,6 Current Spanish PA guidelines recommend that children and youth should accumulate at least 60 minutes of moderate-tovigorous PA (MVPA) daily and reduce screen time to no more than 2 hours daily.…”

“…1,5,6 Current Spanish PA guidelines recommend that children and youth should accumulate at least 60 minutes of moderate-tovigorous PA (MVPA) daily and reduce screen time to no more than 2 hours daily. 7 Nevertheless, Spanish children have PA habits that are far from fulfilling the recommendations.…”