"I love having a healthy lifestyle" - a qualitative study investigating body mass index trajectories from childhood to mid-adulthood.

BACKGROUND: Children with overweight or obesity are at greatly increased risk of experiencing obesity in adulthood but for reasons generally unknown some attain a healthier adult weight. This qualitative study investigated individual, social and environmental factors that might explain diverging body mass index (BMI) trajectories. This knowledge could underpin interventions to promote healthy weight. METHODS: This 2016 study included participants from three adult follow-ups of children who (when 7-15 years) participated in the 1985 Australian Schools Health and Fitness Survey and provided BMI data at each time point. Trajectory-based group modelling identified five BMI trajectories: stable below average, stable average, increasing from average, increasing from very high and decreasing from very high. Between six and 12 participants (38-46 years) from each BMI trajectory group were interviewed (n = 50; 60% women). Thematic analysis guided by a social-ecological framework explored individual, social and environmental influences on diet and physical activity within the work setting. RESULTS: A distinct approach to healthy behaviour was principally identified in the stable and decreasing BMI groups - we term this approach "health identity" (exemplified by "I love having a healthy lifestyle"). This concept was predominant in the stable or decreasing BMI groups when participants explained why work colleagues seemingly did not influence their health behaviour. Participants in the stable and decreasing BMI groups also more commonly reported, bringing home-prepared lunches to work, working or being educated in a health-related field, having a physically active job or situating physical activity within and around work - the latter three factors were common among those who appeared to have a more distinct "health identity". Alcohol, workplace food culture (e.g. morning teas), and work-related stress appeared to influence weight-related behaviours, but generally these factors were similarly discussed across all trajectory groups. CONCLUSION: Work-related factors may influence weight or weight-related behaviours, irrespective of BMI trajectory, but the concept of an individual's "health identity" may help to explain divergent BMI trajectories. "Health identity" and its influence on health behaviour warrants further exploratory work.

Skeletal and hormonal responses to vitamin D supplementation during sunlight deprivation in Antarctic expeditioners.

UNLABELLED: Sunlight deprivation results in vitamin D deficiency but serum vitamin D levels can be maintained above 50 nmol/L when supplemented with 50,000 IU at least every alternate month. INTRODUCTION: Antarctic expeditioners are exposed to prolonged sunlight deprivation resulting in vitamin D deficiency. We hypothesised that monthly dosing of 50,000 IU vitamin D (~1,600 IU daily) will increase serum 25-hydroxyvitamin D (25(OH)D), suppress parathyroid hormone (PTH) and improve bone mineral density (BMD), 50,000 IU alternate months (~800 IU daily) will maintain these measures, while a single 50,000 IU dose pre-departure (~1,00 IU daily) will not be protective. METHODS: This was a randomised double-blind study involving 110 healthy adults: 91 males, mean age 41 years (range 24-65 years) working in Antarctica for up to 12 months, who we administered 50,000 IU vitamin D3 monthly, alternate months or a single dose pre-departure. Serum 25(OH)D, PTH, osteocalcin, CTx and calcium were assessed at baseline, mid- and end of expedition. Proximal femur and lumbar spine BMD were assessed pre- and post-expedition. RESULTS: Baseline 25(OH)D was 59 ± 14 nmol/L. By mid-expedition, 25(OH)D increased by 7 nmol/L in those supplemented monthly (p < 0.05) and remained unchanged in those supplemented in alternate months. In those given a single dose pre-departure, 25(OH)D decreased by 8 nmol/L (p < 0.05) and PTH increased by 27% (p < 0.09). Serum osteocalcin increased by ~22% in all groups but BMD remained unchanged. If serum 25(OH)D was >50 nmol/L at baseline, 25(OH)D was maintained above this level with all regimens. If 25(OH)D was <50 nmol/L at baseline, monthly or alternate month regimens were needed to achieve levels >50 nmol/L, the single pre-departure dose was ineffective. CONCLUSION: During sunlight deprivation of up to 12 months, serum 25(OH)D levels can be maintained above 50 nmol/L when expeditioners are provided with 50,000 I U at least every alternate month.

Crenarchaeota affiliated with group 1.1b are prevalent in coastal mineral soils of the Ross Sea region of Antarctica.

The objective of this study was to examine the presence and diversity of Archaea within mineral and ornithogenic soils from 12 locations across the Ross Sea region. Archaea were not abundant but DNA sufficient for producing 16S rRNA gene clone libraries was extracted from 18 of 51 soil samples, from four locations. A total of 1452 clones were analysed by restriction fragment length polymorphism and assigned to 43 operational taxonomic units from which representatives were sequenced. Archaea were primarily restricted to coastal mineral soils which showed a predominance of Crenarchaeota belonging to group 1.1b (> 99% of clones). These clones were assigned to six clusters (A through F), based on shared identity to sequences in the GenBank database. Ordination indicated that soil chemistry and water content determined archaeal community structure. This is the first comprehensive study of the archaeal community in Antarctic soils and as such provides a reference point for further investigation of microbial function in this environment.

Bacterial diversity associated with ornithogenic soil of the Ross Sea region, Antarctica.

In the Ross Sea region of Antarctica, ornithogenic soils form on land under Adélie Penguin rookeries. Compared with mineral soils of the Ross Sea region, ornithogenic soils are generally high in microbial biomass, organic carbon, and total nitrogen and phosphorus, with high electrical conductivity and large variations in pH. The objective of this study was to assess the bacterial composition of ornithogenic soils from Cape Hallett and Cape Bird in the Ross Sea region using culture-independent methods. Soil clone libraries were constructed and those clones that occurred > or = 3 times were sequenced. The bacterial diversity of the soils was dependent on the presence of penguins. Firmicutes most closely related to the endospore-formers (e.g., Oceanobacillus profundus and Clostridium acidurici) and (or) Gammaproteobacteria belonging to the genus Psychrobacter dominated soils currently occupied with penguins. In contrast, Gammaproteobacteria, closely related to cultured members of the genera Rhodanobacter, Psychrobacter, Dokdonella, and Lysobacter, dominated the soils previously colonized by penguins. Results of this study indicate that despite relatively high nutrient levels and microbial biomass, bacterial communities of ornithogenic soils were not more diverse than those of mineral soils of the Ross Sea region of Antarctica.

Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners.

UNLABELLED: Serum 25(OH)D levels decline without sunlight exposure. We studied 120 expeditioners to Antarctica to determine the skeletal and hormonal responses to sunlight deprivation. With emerging vitamin D insufficiency, serum calcium decreased, PTH increased, and bone loss at the proximal femur was observed. Baseline serum 25(OH)D levels >100 nmol/L prevented vitamin D insufficiency. INTRODUCTION: Vitamin D stores deplete without adequate sunlight exposure unless supplementation is provided. We studied 120 healthy adults who spent a year in Antarctica as a model for sunlight deprivation to define the timing and magnitude of the skeletal and hormonal responses to emerging vitamin D insufficiency. METHODS: Fasting blood samples were assessed at baseline, 6 and 12 months for serum 25-hydroxyvitamin D (25(OH)D), osteocalcin (OC), bone formation (P1NP) and resorption (CTx), PTH and calcium. Lumbar spine and proximal femur BMD was measured using DXA. Differences over time were determined using repeated measures ANOVA. Percent changes were expressed as (Delta value/(value A + value B)/2) x 100. Relationships between outcome measures were determined using Spearman's correlations. RESULTS: Vitamin D insufficiency (<50 nmol/L) was observed in 85% of expeditioners by 6 months when serum calcium decreased and PTH increased (p < 0.01). By 12 months, OC increased by 7.4 +/- 3.0% (p < 0.05), and BMD decreased by 1.0 +/- 2.0% at the total proximal femur (p < 0.05). For those with vitamin D sufficiency at baseline (>50 nmol/L), sunlight deprivation produced vitamin D insufficiency within 4 months unless baseline values were >100 nmol/L. CONCLUSION: Supplementation may be necessary for expeditioners with limited access to UV light.

One year in Antarctica: mucosal immunity at three Australian stations.

The effect of a year's isolation in Antarctica on the human mucosal immune system was assessed during the winter of 1992 at three Australian Antarctic stations: Casey, Davis and Mawson. Saliva samples were collected from each expeditioner prior to their departure from Australia and during each month in Antarctica. The concentrations of salivary immunoglobulins IgA and IgG were significantly different between the three stations, but there were no differences for salivary IgM and albumin. The mean concentrations of IgA were higher at Mawson (P < 0.008), and the mean concentrations of IgG were lower at Davis (P < 0.001) compared with the other stations. Ranges of values observed at the stations over the 12-13 months were similar. The variability of values within individuals showed station differences for salivary IgM and IgG only. The study revealed significant changes in salivary immunoglobulin values over the period in Antarctica, with similar patterns at the three Australian stations. The salivary IgA and IgM levels were lower in the first 4 months in Antarctica (January-April) and increased to maximum values in July-August, before returning to mean levels when isolation was broken in October-November. The patterns of salivary IgA and IgM suggest that stressors due to isolation may play a role in alterations of mucosal immunity in expeditioners in Antarctica.

Polar hands: spontaneous skin fissures closed with cyanoacrylate (Histoacryl Blue) tissue adhesive in Antarctica.

A series of thirteen patients with "polar hands", painful fissuring of fingertips, is documented in Antarctic medical practice together with the results of treatment by cyanoacrylate (Histoacryl Blue) human tissue adhesive. Reduction in tenderness and pain allowing improved finger function and a quicker resolution was observed. Cyanoacrylate is a viable adjunct in the treatment of painful superficial finger fissures.