Physical activity and healthy weight maintenance from childhood to adulthood

The objective of this study was to determine whether change in physical activity was associated with maintaining a healthy weight from childhood to adulthood. This prospective cohort study examined 1,594 young Australian adults (48.9% female) aged 27–36 years who were first examined at age 9–15 years as part of a national health and fitness survey. BMI was calculated from measured height and weight, and physical activity was self-reported at both time points; pedometers were also used at follow-up. Change in physical activity was characterized by calculating the difference between baseline and follow-up z-scores. Change scores were categorized as decreasing (large, moderate), stable, or increasing (large, moderate). Healthy weight was defined in childhood as a BMI less than international overweight cutoff points, and in adulthood as BMI<25 kg/m2. Healthy weight maintainers were healthy weight at both time points. Compared with those who demonstrated large relative decreases in physical activity, females in all other groups were 25–37% more likely to be healthy weight maintainers, although associations differed according to the physical activity measure used at follow-up and few reached statistical significance. Although younger males whose relative physical activity moderately or largely increased were 27–34% more likely to be healthy weight maintainers than those whose relative physical activity largely decreased, differences were not statistically significant. In conclusion, relatively increasing and stable physical activity from childhood to adulthood was only weakly associated with healthy weight maintenance. Examining personal, social, and environmental factors associated with healthy weight maintenance will be an important next step in understanding why some groups avoid becoming overweight.

Estimation of the dietary requirement for vitamin D in healthy adults

Background: Knowledge gaps have contributed to considerable variation among international dietary recommendations for vitamin D.

Objective: We aimed to establish the distribution of dietary vitamin D required to maintain serum 25-hydroxyvitamin D [25(OH)D] concentrations above several proposed cutoffs (ie, 25, 37.5, 50, and 80 nmol/L) during wintertime after adjustment for the effect of summer sunshine exposure and diet.

Design: A randomized, placebo-controlled, double-blind 22-wk intervention study was conducted in men and women aged 20–40 y (n = 238) by using different supplemental doses (0, 5, 10, and 15 µg/d) of vitamin D3 throughout the winter. Serum 25(OH)D concentrations were measured by using enzyme-linked immunoassay at baseline (October 2006) and endpoint (March 2007).

Results: There were clear dose-related increments (P < 0.0001) in serum 25(OH)D with increasing supplemental vitamin D3. The slope of the relation between vitamin D intake and serum 25(OH)D was 1.96 nmol·L–1·µg–1 intake. The vitamin D intake that maintained serum 25(OH)D concentrations of >25 nmol/L in 97.5% of the sample was 8.7 µg/d. This intake ranged from 7.2 µg/d in those who enjoyed sunshine exposure, 8.8 µg/d in those who sometimes had sun exposure, and 12.3 µg/d in those who avoided sunshine. Vitamin D intakes required to maintain serum 25(OH)D concentrations of >37.5, >50, and >80 nmol/L in 97.5% of the sample were 19.9, 28.0, and 41.1 µg/d, respectively.

Conclusion: The range of vitamin D intakes required to ensure maintenance of wintertime vitamin D status [as defined by incremental cutoffs of serum 25(OH)D] in the vast majority (>97.5%) of 20–40-y-old adults, considering a variety of sun exposure preferences, is between 7.2 and 41.1 µg/d.

Longitudinal examination of physical and relational aggression as precursors to later problem behaviors in adolescents

Research has addressed the consequences of being a victim of physical and relational aggression but less so the consequences of being an aggressor during adolescence. Consequently, relatively little is known about the extent to which aggression in early adolescence increases the risk of later aggression and other psychosocial problems. This study involves a representative sample of seventh- and ninth-grade students from Washington State ( N = 1,942). Students were surveyed on recruitment and then again 1 and 2 years later to learn about ongoing behavior problems, substance use, depression, and self-harm behaviors. Surveys also included measures of several hypothesized promotive factors: attachment to family, school commitment, and academic achievement. Findings suggest that being physically and/or relationally aggressive in grades 7 to 9 increases the risk of aggression and possibly other problem behaviors after accounting for age, gender, race, and a prior measure of each outcome. Independent promotive effects were observed in most analyses, although family attachment appeared a less robust predictor overall. Implications for prevention include acting on the behavior itself and enhancing promotive influences to lessen the risk of agression and other related problems.

Effect of zinc supplementation on the immune status of healthy older individuals aged 55–70 years : the ZENITH Study

Aging is associated with alterations in the immune system, effects which may be exacerbated by inadequate zinc (Zn) status. We examined the relationship between Zn status and markers of immunity and the effect of supplementation with 15 mg or 30 mg Zn/d for 6 months on immune status in healthy individuals. Zn status was assessed by dietary intake and biochemical indices. Immune status was assessed by multiple flow cytometric methods. At baseline, Zn concentration was positively associated with lymphocyte subpopulation counts and T-lymphocyte activation. Zn supplementation of 30 mg/d significantly lowered B-lymphocyte count, albeit at month 3 only. Lower doses of Zn (15 mg Zn/d) significantly increased the ratio of CD4 to CD8 T lymphocytes at month 6. Overall, these findings suggest that total Zn intake (diet plus supplementation) of up to 40 mg Zn/d do not have significant long-term effects on immune status in apparently healthy persons aged 55–70 years.

Whole blood analysis of phagocytosis, apoptosis, cytokine production, and leukocyte subsets in healthy older men and women: the ZENITH study

Few studies to date have examined age-related changes in markers of immune status in healthy older individuals. The immune status of 93 healthy individuals aged 55–70 years was assessed by two- and three-color flow cytometry and biochemical analysis. There were significant age effects (p ≤.05) on monocyte phagocytic activity and cluster of differentiation (CD) 3/human leukocyte antigen-D-related (HLA-DR) late-activated T lymphocytes (% expression). There was a significant (p ≤ 0.1) Age x Sex interaction in absolute counts (x 10⁹/L) of CD3/CD8 total cytotoxic T lymphocytes (CTL), the CD4 T- helper to CD8 CTL ratio, the CD3/CD4/CD45RA naïve T helper to CD3/CD4/CD45RO memory T helper lymphocyte ratio, and interleukin (IL)-1ß (% expression) by activated monocytes. The study shows that alterations in markers of immune status occur between 55 and 70 years, and provides reference values for the lymphocyte measures in healthy men and postmenopausal women in this age group. The study further highlights the need for sex-specific reference ranges for such markers.

Sociocultural influences on body dissatisfaction and body change behaviors among Malaysian adolescents

Little research on body dissatisfaction and body change behaviors, and the sociocultural influences on them, has been undertaken in non-Western contexts. The current study investigated these variables and the relationships between them among a sample of 529 Malaysian high school students (103 Malays, 344 Chinese and 82 Indians), who completed a set of measures in classroom settings. Chinese girls were more dissatisfied with their bodies than Chinese boys, but no gender difference was found for Malay and Indian participants. Girls were more likely to engage in behaviors to lose weight, and boys were more likely to engage in behaviors to increase muscle. The influence of sociocultural factors on body dissatisfaction and body change behaviors was limited and varied across both sex and ethnicity. Findings are discussed in relation to Western research, and it is concluded that cultural nuances need to be considered when investigating these phenomena.

Long-term effect of calcium-vitamin D3 fortified milk on blood pressure and serum lipid concenstrations in healthy older men

Background/Objectives:
Some epidemiological and clinical studies have shown that increased dairy consumption or calcium and/or vitamin D supplementation can have a beneficial effect on blood pressure, and lipid and lipoprotein concentrations. The aim of this study was to assess the long-term effects of calcium-vitamin D3 fortified milk on blood pressure and lipid-lipoprotein concentrations in community-dwelling older men.

Subjects/Methods:
This is a substudy of a 2-year randomized controlled trial in which 167 men aged >50 years were assigned to receive either 400 ml per day of reduced fat (approx1%) milk fortified with approximately 1000 mg of calcium and 800 IU of vitamin D3 or to a control group receiving no additional fortified milk. Weight, blood pressure, lipid and lipoprotein concentrations were measured every 6 months. Participants on lipid-lowering (n=32) or antihypertensive medication (n=39) were included, but those who commenced, increased or decreased their medication throughout the intervention were excluded (n=27).

Results:
In the 140 men included in this study (milk, n=73; control, n=67), there were no significant effects of the calcium-vitamin D3 fortified milk on weight, systolic or diastolic blood pressure, total cholesterol, high-density lipoprotein or low-density lipoprotein cholesterol or triglyceride concentrations at any time throughout the intervention. Similar results were observed after excluding men taking antihypertensive or lipid-lowering medication or limiting the analysis to those with baseline calcium intakes <1000 mg per day and/or with hypovitaminosis D (25(OH)D <75 nmol/l).

Conclusions:
Supplementation with reduced-fat calcium-vitamin D3 fortified milk did not have a beneficial (nor detrimental) effect on blood pressure, lipid or lipoprotein concentrations in healthy community-dwelling older men.

Moving beyond 'rates, roads and rubbish' : how do local governments make choices about healthy public policy to prevent obesity?

While the causes of obesity are well known traditional education and treatment strategies do not appear to be making an impact. One solution as part of a broader complimentary set of strategies may be regulatory intervention at local government level to create environments for healthy nutrition and increased physical activity. Semi structured interviews were conducted with representatives of local government in Australia. Factors most likely to facilitate policy change were those supported by external funding, developed from an evidence base and sensitive to community and market forces. Barriers to change included a perceived or real lack of power to make change and the complexity of the legislative framework. The development of a systematic evidence base to provide clear feedback on the size and scope of the obesity epidemic at a local level, coupled with cost benefit analysis for any potential regulatory intervention, are crucial to developing a regulatory environment which creates the physical and social environment required to prevent obesity.

Socioeconomic position and children's physical activity and sedentary behaviors : longitudinal findings from the CLAN study

Background: This study aimed to examine cross-sectional and longitudinal associations between socioeconomic position (SEP) and physical activity and sedentary behaviors amongst children and adolescents.

Methods: Maternal education was reported by parents of 184 5-6 year-old and 358 10-12 year-old children in 2001. In 2001 and 2004, physical activity was assessed by accelerometry. Older children self-reported and parents of younger children proxy-reported physical activity and television (TV) viewing behaviors. Linear regression was used to predict physical activity and sedentary behaviors, and changes in these behaviors, from maternal education.

Results: Among all children, accelerometer-determined and self/parent-reported moderate and vigorous physical activity declined over three years. Girls of higher SEP demonstrated greater decreases in TV viewing behaviours than those of low SEP. In general, no prospective associations were evident between SEP and objectively-assessed physical activity. A small number of prospective associations were noted between SEP and self-reported physical activity, but these were generally weak and inconsistent in direction.

Conclusions: This study did not find strong evidence that maternal education was cross-sectionally or longitudinally predictive of children’s physical activity or sedentary behaviors. Given the well-documented inverse relationship of SEP with physical activity levels in adult samples, findings suggest that such disparities may emerge after adolescence.

Women's work. Maintaining a healthy body weight

This study describes women's perceptions of the supports and barriers to maintaining a healthy weight among currently healthy weight women from urban and rural socio-economically disadvantaged areas. Using focus groups and interviews, we asked women about their experiences of maintaining a healthy weight. Overwhelmingly, women described their healthy weight practices in terms of concepts related to work and management. The theme of ‘managing health’ comprised issues of managing multiple responsibilities, time, and emotions associated with healthy practices. Rural women faced particular difficulties in accessing supports at a practical level (for example, lack of childcare) and due to the gendered roles they enacted in caring for others. Family background (in particular, mothers’ attitudes to food and weight) also appeared to influence perceptions about healthy weight maintenance. In the context of global increases in the prevalence of obesity, the value of initiatives aimed at supporting healthy weight women to maintain their weight should not be under-estimated. Such initiatives need to work within the social and personal constraints that women face in maintaining good health.

Examination of EMG normalisation methods for the study of the posterior and posterolateral neck muscles in healthy controls

The purpose of this study was to examine the reliability of normalisation methods used in the study of the posterior and posterolateral neck muscles in a group of healthy controls. Six asymptomatic male subjects performed a total of 12 maximum voluntary isometric contractions (MVIC) and 60%-submaximal isometric contractions (60%-MVIC) against the torque arm of an isokinetic dynamometer whilst surface and intramuscular electromyography (EMG) was recorded unilaterally from representative posterior and posterolateral locations. Reliability was calculated using intra-class correlation coefficient (ICC), relative standard error of measurement (%SEM) and relative coefficient of variation (%CV). Maximal torque output was found to be highly reliable in the directions of extension and right lateral bending when the first of three MVIC contractions was excluded. When averaged across contraction direction, high reliability was found for both surface (MVIC: ICC = 0.986, %SEM = 7.5, %CV = 9.2; 60%-MVIC: ICC = 0.975, %SEM = 10, %CV = 13.7) and intramuscular (MVIC: ICC = 0.910, %SEM = 20, %CV = 19.1; 60%-MVIC: ICC = 0.952, %SEM = 16.5, %CV = 13.5) electrodes. Intramuscular electrodes displayed the least reliability in right lateral bending. The use of visual feedback markedly increased the reliability of 60%-MVIC contractions.

Healthy minds : methods of investigation

We'll start this chapter by looking at emthods used to assess mental disorders, using depression an an example. We will then look at ways of evaluating psychological interventions.  Finally we will outline ways that healthy minds have been investigated, drawing particularly on research methods that study happiness, personal strengths and spirituality.