Browsing by Subject "adiposity"

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  • Dumuid, Dorothea; Stanford, Tyman E.; Pedisic, Zeljko; Maher, Carol; Lewis, Lucy K.; Martin-Fernandez, Josep-Antoni; Katzmarzyk, Peter T.; Chaput, Jean-Philippe; Fogelholm, Mikael; Standage, Martyn; Tremblay, Mark S.; Olds, Timothy (2018)
    Background: Daily activity data are by nature compositional data. Accordingly, they occupy a specific geometry with unique properties that is different to standard Euclidean geometry. This study aimed to estimate the difference in adiposity associated with isotemporal reallocation between daily activity behaviours, and to compare the findings from compositional isotemporal subsitution to those obtained from traditional isotemporal substitution. Methods: We estimated the differences in adiposity (body fat%) associated with reallocating fixed durations of time (isotemporal substitution) between accelerometer-measured daily activity behaviours (sleep, sedentary time and light and moderate-to-vigorous physical activity (MVPA)) among 1728 children aged 9-11 years from Australia, Canada, Finland and the UK (International Study of Childhood Obesity, Lifestyle and the Environment, 2011-2013).We generated estimates from compositional isotemporal substitution models and traditional non-compositional isotemporal substitution models. Results: Both compositional and traditional models estimated a positive (unfavourable) difference in body fat% when time was reallocated from MVPA to any other behaviour. Unlike traditional models, compositional models found the differences in estimated adiposity (1) were not necessarily symmetrical when an activity was being displaced, or displacing another (2) were not linearly related to the durations of time reallocated, and (3) varied depending on the starting composition. Conclusion: The compositional isotemporal model caters for the constrained and therefore relative nature of activity behaviour data and enables all daily behaviours to be included in a single statistical model. The traditional model treats data as real variables, thus the constrained nature of time is not accounted for, nor reflected in the findings. Findings from compositional isotemporal substitution support the importance of MVPA to children's health, and suggest that while interventions to increase MVPA may be of benefit, attention should be directed towards strategies to avoid decline in MVPA levels, particularly among already inactive children. Future applications of the compositional model can extend from pair-wise reallocations to other configurations of time-reallocation, for example, increasing MVPA at the expense of multiple other behaviours.
  • Dumuid, Dorothea; Stanford, Tyman E; Pedišić, Željko; Maher, Carol; Lewis, Lucy K; Martín-Fernández, Josep-Antoni; Katzmarzyk, Peter T; Chaput, Jean-Philippe; Fogelholm, Mikael; Standage, Martyn; Tremblay, Mark S; Olds, Timothy (BioMed Central, 2018)
    Abstract Background Daily activity data are by nature compositional data. Accordingly, they occupy a specific geometry with unique properties that is different to standard Euclidean geometry. This study aimed to estimate the difference in adiposity associated with isotemporal reallocation between daily activity behaviours, and to compare the findings from compositional isotemporal subsitution to those obtained from traditional isotemporal substitution. Methods We estimated the differences in adiposity (body fat%) associated with reallocating fixed durations of time (isotemporal substitution) between accelerometer-measured daily activity behaviours (sleep, sedentary time and light and moderate-to-vigorous physical activity (MVPA)) among 1728 children aged 9–11 years from Australia, Canada, Finland and the UK (International Study of Childhood Obesity, Lifestyle and the Environment, 2011–2013). We generated estimates from compositional isotemporal substitution models and traditional non-compositional isotemporal substitution models. Results Both compositional and traditional models estimated a positive (unfavourable) difference in body fat% when time was reallocated from MVPA to any other behaviour. Unlike traditional models, compositional models found the differences in estimated adiposity (1) were not necessarily symmetrical when an activity was being displaced, or displacing another (2) were not linearly related to the durations of time reallocated, and (3) varied depending on the starting composition. Conclusion The compositional isotemporal model caters for the constrained and therefore relative nature of activity behaviour data and enables all daily behaviours to be included in a single statistical model. The traditional model treats data as real variables, thus the constrained nature of time is not accounted for, nor reflected in the findings. Findings from compositional isotemporal substitution support the importance of MVPA to children’s health, and suggest that while interventions to increase MVPA may be of benefit, attention should be directed towards strategies to avoid decline in MVPA levels, particularly among already inactive children. Future applications of the compositional model can extend from pair-wise reallocations to other configurations of time-reallocation, for example, increasing MVPA at the expense of multiple other behaviours.
  • Jarvis, David; Mitchell, Jonathan S.; Law, Philip J.; Palin, Kimmo; Tuupanen, Sari; Gylfe, Alexandra; Hanninen, Ulrika A.; Cajuso, Tatiana; Tanskanen, Tomas; Kondelin, Johanna; Kaasinen, Eevi; Sarin, Antti-Pekka; Kaprio, Jaakko; Eriksson, Johan G.; Rissanen, Harri; Knekt, Paul; Pukkala, Eero; Jousilahti, Pekka; Salomaa, Veikko; Ripatti, Samuli; Palotie, Aarno; Järvinen, Heikki; Renkonen-Sinisalo, Laura; Lepistö, Anna; Bohm, Jan; Mecklin, Jukka-Pekka; Al-Tassan, Nada A.; Palles, Claire; Martin, Lynn; Barclay, Ella; Farrington, Susan M.; Timofeeva, Maria N.; Meyer, Brian F.; Wakil, Salma M.; Campbell, Harry; Smith, Christopher G.; Idziaszczyk, Shelley; Maughan, Timothy S.; Kaplan, Richard; Kerr, Rachel; Kerr, David; Buchanan, Daniel D.; Win, Aung K.; Hopper, John L.; Jenkins, Mark A.; Lindor, Noralane M.; Newcomb, Polly A.; Gallinger, Steve; Conti, David; Schumacher, Fred; Casey, Graham; Taipale, Jussi; Aaltonen, Lauri A.; Cheadle, Jeremy P.; Dunlop, Malcolm G.; Tomlinson, Ian P.; Houlston, Richard S. (2016)
    Background: Observational studies have associated adiposity with an increased risk of colorectal cancer (CRC). However, such studies do not establish a causal relationship. To minimise bias from confounding we performed a Mendelian randomisation (MR) analysis to examine the relationship between adiposity and CRC. Methods: We used SNPs associated with adult body mass index (BMI), waist-hip ratio (WHR), childhood obesity and birth weight as instrumental variables in a MR analysis of 9254 CRC cases and 18 386 controls. Results: In the MR analysis, the odds ratios (ORs) of CRC risk per unit increase in BMI, WHR and childhood obesity were 1.23 (95% CI: 1.02-1.49, P = 0.033), 1.59 (95% CI: 1.08-2.34, P = 0.019) and 1.07 (95% CI: 1.03-1.13, P = 0.018), respectively. There was no evidence for association between birth weight and CRC (OR = 1.22, 95% CI: 0.89-1.67, P = 0.22). Combining these data with a concurrent MR-based analysis for BMI and WHR with CRC risk (totalling to 18 190 cases, 27 617 controls) provided increased support, ORs for BMI and WHR were 1.26 (95% CI: 1.10-1.44, P = 7.7 x 10(-4)) and 1.40 (95% CI: 1.14-1.72, P = 1.2 x 10(-3)), respectively. Conclusions: These data provide further evidence for a strong causal relationship between adiposity and the risk of developing CRC highlighting the urgent need for prevention and treatment of adiposity.
  • Luotola, Kari; Piltonen, Terhi T; Puurunen, Johanna; Morin-Papunen, Laure C; Tapanainen, Juha S (2018)
    Objective: To study the associations between androgens, glucose homeostasis, inflammation and statin treatment in women with polycystic ovary syndrome (PCOS). Design and methods: Oral glucose tolerance tests, androgens, hs-CRP and interleukin-1 receptor antagonist (IL-1Ra) were analyzed at baseline and after 6months of atorvastatin (20 mg/d) or placebo treatment in 27 women with PCOS. Results: Testosterone associated with insulin resistance measured with ISIMatsuda independently of BMI, age and SHBG concentrations and the full model, including IL-1Ra, hs-CRP and HDL-C, also showed independency of BMI and waist circumference (p≤.042). Free androgen index (FAI) associated with ISIMatsuda independently of adiposity (p≤.025) but in the full model with waist circumference the association was insignificant. ISIMatsuda decreased with testosterone >1.2nmol/l compared with lower levels at baseline (p=.043) and at six months (p=.003). Accordingly, 30-minute insulin levels were increased with moderately elevated testosterone independently of adiposity (p≤.046). Increased fasting glucose and AUC insulin associated with statin treatment independently of adiposity and the associations attenuated after adjusting for testosterone.  Conclusions: Moderately elevated testosterone concentrations together with obesity-related inflammatory factors modify glucose homeostasis by increasing insulin resistance and early insulin secretion.
  • Johansson, Edvard; Böckerman, Petri; Kiiskinen, Urpo; Heliövaara, Markku (Svenska handelshögskolan, 2007)
    Working Papers
    In this paper, we re-examine the relationship between overweight and labour market success, using indicators of individual body composition along with BMI (Body Mass Index). We use the dataset from Finland in which weight, height, fat mass and waist circumference are not self-reported, but obtained as part of the overall health examination. We find that waist circumference, but not weight or fat mass, has a negative effect on wages for women, whereas all measures of obesity have negative effects on women’s employment probabilities. For men, the only obesity measure that is significant for men’s employment probabilities is fat mass. One interpretation of our findings is that the negative wage effects of overweight on wages run through the discrimination channel, but that the negative effects of overweight on employment have more to do with ill health. All in all, measures of body composition provide a more refined picture about the effects of obesity on wages and employment.