Partnering and parenting transitions in Australian men and women: associations with changes in weight, domain-specific physical activity and sedentary behaviours

Background: Partnering and parenting are important life-stage transitions often accompanied by changes in social networks, roles and responsibilities. There have been no longitudinal studies examining associations of partnering and parenting with changes in domain-specific physical activity (PA) and sedentary behaviours, and our understanding of whether these transitions are associated with weight change is limited. Methods: Two thousand one hundred and twenty-four Australian adults from a national cohort (mean age 31.7 (2.7) years, 47.5% male) completed questionnaires at baseline (2004-06) and follow-up (2009-11), reporting marital and parental status. Weight (kg) was measured at baseline and self-reported at follow-up. PA and sedentary behaviours (sitting and television (TV) viewing) were self-reported in a subset (n = 1221). Linear regression estimated the longitudinal associations of parenting and partnering transitions with PA, sedentary behaviours and weight at follow-up, adjusted for baseline value of the respective outcome variable, age, education, follow-up duration and other life-stage transition. Results: During the 5-year follow-up, 17.3% men and 12.9% women partnered, and 27.3% men and 19.1% women had their first child. Compared to staying not partnered, partnering was associated with an increase in total PA (177.5mins/week, 95% Confidence Interval (CI) 18.0 to 337.0) among men and a greater weight gain (2.2 kg, 95% CI 0.6 to 3.7) among women. Compared to remaining child-free, having a first child was associated with greater reductions in total PA (- 123.9mins/week, 95% CI - 248.8 to 1.1) and TV viewing time (- 27.0mins/day, 95% CI - 50.6 to - 3.3) among men. Women who had their first child had greater weight gain (1.4 kg, 95% CI 0.1 to 2.7) but spent less time sitting (- 103.8mins/day, 95% CI - 135.5 to - 72.1) than those remaining child-free. For women, having additional children was associated with less sitting time (- 39.4mins/week, 95% CI - 66.0 to - 12.8) than having the same number of children. Conclusions: Partnering was associated with an increase in men's total PA and women's weight. Transitions into parenthood with a first child or additional children were associated with potentially health-impairing changes in weight and PA, but health-promoting changes in sedentary behaviours. Future PA promotion strategies should pay attention to men who had their first child to mitigate declining total PA

The association between muscular power from childhood to adulthood and adult measures of glucose homeostasis

This study aimed to assess whether the longitudinal association between childhood muscular fitness and adult measures of glucose homeostasis persist despite changes in muscular fitness across the life course. This prospective longitudinal study included 586 participants who had their muscular power (standing long jump distance), cardiorespiratory fitness (CRF), and waist circumference measured as children (aged 9, 12, 15 years) and again 20 years later as adults. In adulthood, these participants also provided a fasting blood sample which was tested for glucose and insulin. Glucose homeostasis measures including insulin resistance (HOMA2-IR) and beta cell function (HOMA2-β) were estimated. Child and adult muscular power levels were separated into thirds, and tracking groups (persistently low, decreasing, persistently moderate, increasing, and persistently high) were created. Sex-stratified multivariable linear regression models were used to examine the association between muscular power tracking groups and adult measures of glucose homeostasis. Compared with males with persistently high muscular power, males with increasing and persistently low muscular power had higher fasting insulin (increasing: β = 1.12 mU/L, P = .04; persistently low: β = 2.12 mU/L, P = .001) and HOMA2-β (increasing: β = 8.50%, P = .03; persistently low: β = 11.27%, P = .01) independent of CRF and males with persistently low muscular power had greater fasting insulin (β = 1.22 mU/L, P = .02) and HOMA2-IR (β = 0.14, P = .02) independent of waist circumference. Non-significant associations were present for females. For males, maintaining persistently high muscular power between childhood and adulthood could lead to a healthier adult glucose homeostasis profile

The association between grip strength measured in childhood, young- and mid-adulthood and prediabetes or type 2 diabetes in mid-adulthood

Background: Although low child and adult grip strength is associated with adverse cardiometabolic health, how grip strength across the life course associates with type 2 diabetes is unknown. This study identified the relative contribution of grip strength measured at specific life stages (childhood, young adulthood, mid-adulthood) with prediabetes or type 2 diabetes in mid-adulthood. Methods: Between 1985 and 2019, 263 participants had their grip strength measured using an isometric dynamometer in childhood (9-15 years), young adulthood (28-36 years) and mid-adulthood (38-49 years). In mid-adulthood, a fasting blood sample was collected and tested for glucose and glycated haemoglobin (HbA1c). Participants were categorized as having prediabetes or type 2 diabetes if fasting glucose levels were ≥ 5.6 mmol or if HbA1c levels were ≥ 5.7% (≥ 39 mmol/mol). A Bayesian relevant life course exposure model examined the association between lifelong grip strength and prediabetes or type 2 diabetes. Results: Grip strength at each time point was equally associated with prediabetes or type 2 diabetes in mid-adulthood (childhood: 37%, young adulthood: 36%, mid-adulthood: 28%). A one standard deviation increase in cumulative grip strength was associated with 34% reduced odds of prediabetes or type 2 diabetes in mid-adulthood (OR 0.66, 95% credible interval 0.40, 0.98). Conclusions: Greater grip strength across the life course could protect against the development of prediabetes and type 2 diabetes. Strategies aimed at increasing muscular strength in childhood and maintaining behaviours to improve strength into adulthood could improve future cardiometabolic health. The Association Between Grip Strength Measured in Childhood, Young- and Mid-adulthood and Prediabetes or Type 2 Diabetes in Mid-adulthood

The role of rewilding in mitigating hydrological extremes: State of the evidence

Landscape rewilding has the potential to help mitigate hydrological extremes by allowing natural processes to function. Our systematic review assessed the evidence base for rewilding-driven mitigation of high and low flows. The review uncovers a lack of research directly addressing rewilding, but highlights research in analogue contexts which can, with caution, indicate the nature of change. There is a lack of before-after studies that enable deeper examination of temporal trajectories and legacy effects, and a lack of research on the scrub and shrubland habitats common in rewilding projects. Over twice as much evidence is available for high flows compared to low flows, and fewer than one third of studies address high and low flows simultaneously, limiting our understanding of co-benefits and contrasting effects. Flow magnitude variables are better represented within the literature than flow timing variables, and there is greater emphasis on modeling for high flows, and on direct measurement for low flows. Most high flow studies report a mitigating effect, but with variability in the magnitude of effect, and some exceptions. The nature of change for low flows is more complex and suggests a higher potential for increased low flow risks associated with certain trajectories but is based on a very narrow evidence base. We recommend that future research aims to: capture effects on both high and low flow extremes for a given type of change; analyze both magnitude and timing characteristics of flow extremes; and examine temporal trajectories (before and after data) ideally using a full before-after-control-impact design. This article is categorized under: Human Water > Value of Water Science of Water > Hydrological Processes Science of Water > Water Extremes Water and Life > Conservation, Management, and Awareness

Risk factors for left ventricular dysfunction in adulthood: role of low birth weight

Aims: This study aimed to determine the relationship of low birth weight (LBW) with adult cardiac structure and function andinvestigate potential causal pathways.Methods and results: A population-based sample of 925 Australians (41.3% male) were followed from childhood (aged7–15 years) to young adulthood (aged 26–36 years) and mid-adulthood (aged 36–50 years). Left ventricular (LV) globallongitudinal strain (GLS, %), LV mass index (LVMi, g/m2.7), LV filling pressure (E/e╯), and left atrial volume index (g/m2) weremeasured by transthoracic echocardiography in mid-adulthood. Birth weight category was self-reported in young adulthoodand classified as low (≤5 lb or ≤2270 g), normal (5–8 lb or 2271–3630 g), and high (>8 lb or >3630 g). Of the 925participants, 7.5% (n = 69) were classified as LBW. Compared with participants with normal birth weight, those with LBWhad 2.01-fold (95% confidence interval: 1.19, 3.41, P = 0.009) higher risks of impaired GLS (GLS > 18%) and 2.63-fold(95% confidence interval: 0.89, 7.81, P = 0.08) higher risks of LV hypertrophy (LVMi > 48 g/m2.7 in men or >44 g/m2.7 inwomen) in adulthood, independent of age, sex, and any socio-economic factors. Participants with LBW significantlyincreased body fat from childhood to adulthood relative to their peers and had greater levels of triglycerides, fastingglucose, and arterial stiffness in adulthood. These risk factors were the strongest mediators and explained 54% of the LBWeffect size on adult GLS and 33% of the LBW effect size on LVMi. The remaining of these associations was independent ofany of the measured risk factors.Conclusions: Low birth weight was associated with impaired cardiac structure and function in mid-adulthood. This association was only partially explained by known risk factors

Cross-sectional associations between dietary fat-related behaviors and continuous metabolic syndrome score among young Australian adults

Dietary guidelines recommend removing visible fat from meat, choosing low-fat options and cooking with oil instead of butter. This study examined cross-sectional associations between fat-related eating behaviors and a continuous metabolic syndrome (cMetSyn) score among young adults. During 2004⁻2006, 2071 participants aged 26⁻36 years reported how often they trimmed fat from meat, consumed low-fat dairy products and used different types of fat for cooking. A fasting blood sample was collected. Blood pressure, weight and height were measured. To create the cMetSyn score, sex-specific principal component analysis was applied to normalized risk factors of the harmonized definition of metabolic syndrome. Higher score indicates higher risk. For each behavior, differences in mean cMetSyn score were calculated using linear regression adjusted for confounders. Analyses were stratified by weight status (Body mass index (BMI) Trend = 0.013) among participants who were healthy weight and frequency of using canola/sunflower oil for cooking (PTrend = 0.008) among participants who were overweight/obese. Trimming fat from meat, cooking with olive oil, cooking with butter, and consuming low-fat dairy products were not associated with cMetSyn score. Among young adults, following fat-related dietary recommendations tended to not be associated with metabolic risk

The association between muscular power from childhood to adulthood and adult measures of glucose homeostasis

This study aimed to assess whether the longitudinal association between childhood muscular fitness and adult measures of glucose homeostasis persist despite changes in muscular fitness across the life course. This prospective longitudinal study included 586 participants who had their muscular power (standing long jump distance), cardiorespiratory fitness (CRF), and waist circumference measured as children (aged 9, 12, 15 years) and again 20 years later as adults. In adulthood, these participants also provided a fasting blood sample which was tested for glucose and insulin. Glucose homeostasis measures including insulin resistance (HOMA2-IR) and beta cell function (HOMA2-beta) were estimated. Child and adult muscular power levels were separated into thirds, and tracking groups (persistently low, decreasing, persistently moderate, increasing, and persistently high) were created. Sex-stratified multivariable linear regression models were used to examine the association between muscular power tracking groups and adult measures of glucose homeostasis. Compared with males with persistently high muscular power, males with increasing and persistently low muscular power had higher fasting insulin (increasing: beta = 1.12 mU/L, P = .04; persistently low: beta = 2.12 mU/L, P = .001) and HOMA2-beta (increasing: beta = 8.50%, P = .03; persistently low: beta = 11.27%, P = .01) independent of CRF and males with persistently low muscular power had greater fasting insulin (beta = 1.22 mU/L, P = .02) and HOMA2-IR (beta = 0.14, P = .02) independent of waist circumference. Non-significant associations were present for females. For males, maintaining persistently high muscular power between childhood and adulthood could lead to a healthier adult glucose homeostasis profile