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Validation and application of objective measures of obesity and physical activity: studies in pregnant and non-pregnant adults and in infants
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. (Genetic Epidemiology and Clinical Research Group, GECRG)
2011 (English)Doctoral thesis, comprehensive summary (Other academic)Alternative title
Validering och tillämpning av objektiva mätmetoder för obesitas och fysisk aktiviet : studier av gravida och icke-gravida vuxna och av spädbarn (Swedish)
Abstract [en]

Background Excess adipose tissue and low physical activity are two major determinants for chronic diseases such as type 2 diabetes and cardiovascular disease.  Understanding these relationships requires accurate and precise measures of body composition and physical activity, and most existing observational studies lack such measures. Paper I to III in this thesis addresses the validity of measures of physical activity and abdominal adipose mass. In paper IV and V, we explore the relationships between obesity and physical activity on metabolic health in non-pregnant and pregnant women and their offspring.

Methods and Results Two hundred men and women representative of the Northern Sweden EPIC cohort were recruited for Paper I. A questionnaire on physical activity (PAQ) was validated against objectively measured physical activity energy expenditure (PAEE). A categorical physical activity index (Cambridge index) calculated from PAQ showed strongest correlation with PAEE (r=0.33 p<0.05). In Paper II, abdominal adiposity were assessed in 29 adult men and women using anthropometric measurements, dual energy x-ray absorptiometry (DXA) and ultrasound and were compared to computed tomography (CT). Waist circumference showed the highest correlation with CT-assessed visceral (r=0.85, p<0.0001) and subcutaneous adipose tissue (r=0.86, p<0.0001). Adipose thickness was best assessed with ultrasound. In Paper III, the validity of a wrist-worn triaxial accelerometer was assessed in 32 pregnant and 74 non-pregnant women using double-labeled water method (DLW) as the criterion measure. The output from the accelerometer explained 24% (p <0.001) of the variation in PAEE in non-pregnant and 11% (p<0.05) in the pregnant women. In Paper IV, 35 pregnant and 73 non-pregnant women underwent a 75g oral glucose tolerance test and habitual energy expenditure and physical activity was assessed objectively. Total physical activity was inversely associated with early insulin response in both pregnant (r=-0.47, p=0.007) and non-pregnant (r=-0.36, p=0.004) women. In, Paper V, 32 women and their offspring (n=33) were studied 4 months post-partum. Body composition was quantified using DXA in the women and air-displacement plethysmography  in the infants. Mid-pregnancy weight gain was significantly associated with infant fat mass (r=0.41, p=0.022), whereas late-pregnancy weight gain associated to infant fat-free mass (r=0.37, p=0.04).

Conclusion This work describes new methods as well as conventional anthropometric estimates and a questionnaire, that provide relatively strong estimates of body composition and physical activity which could be used in larger studies. Pregnant women were shown to have more sedentary behavior than non-pregnant but physical activity appeared to have equal effect on glucose homeostasis in both groups, which may help guide lifestyle interventions in pregnancy. The impact of weight gain during the different trimesters seems to differentially affect the offspring’s body composition in early infancy, which might give us clues to when different aspects of fetal development and growth occur and how modifiable lifestyle behaviors might be intervened upon to improve long-term health.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet , 2011. , 110 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1422
Keyword [en]
physical activity, validation, body composition, abdominal adipose tissue, methods, accelerometer, pregnancy, insulin sensitivity, offspring
Identifiers
URN: urn:nbn:se:umu:diva-43770ISBN: 978-91-7459-216-0OAI: oai:DiVA.org:umu-43770DiVA: diva2:416491
Public defence
2011-06-07, Bergasalen, Norrlands universitetssjukhus, Umeå, 09:00 (English)
Opponent
Supervisors
Note
EmbargoAvailable from: 2011-05-13 Created: 2011-05-09 Last updated: 2012-04-04Bibliographically approved
List of papers
1. Validity of a short questionnaire to assess physical activity in 10 European countries
Open this publication in new window or tab >>Validity of a short questionnaire to assess physical activity in 10 European countries
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2012 (English)In: European Journal of Epidemiology, ISSN 0393-2990, E-ISSN 1573-7284, Vol. 27, no 1, 15-25 p.Article in journal (Refereed) Published
Abstract [en]

To accurately examine associations of physical activity (PA) with disease outcomes, a valid method of assessing free-living activity is required. We examined the validity of a brief PA questionnaire (PAQ) used in the European Prospective Investigation into Cancer and Nutrition (EPIC). PA energy expenditure (PAEE) and time spent in moderate and vigorous physical activity (MVPA) was measured in 1,941 healthy individuals from 10 European countries using individually-calibrated combined heart-rate and movement sensing. Participants also completed the short EPIC-PAQ, which refers to past year's activity. Pearson (r) and Spearman (sigma) correlation coefficients were calculated for each country, and random effects meta-analysis was used to calculate the combined correlation across countries to estimate the validity of two previously- and one newly-derived ordered, categorical PA indices ("Cambridge index", "total PA index", and "recreational index") that categorized individuals as inactive, moderately inactive, moderately active, or active. The strongest associations with PAEE and MVPA were observed for the Cambridge index (r = 0.33 and r = 0.25, respectively). No significant heterogeneity by country was observed for this index (I-2 = 36.3%, P = 0.12; I-2 = 0.0%, P = 0.85), whereas heterogeneity was suggested for other indices (I-2 > 48%, P < 0.05, I-2 > 47%, P < 0.05). PAEE increased linearly across self-reported PA categories (P for trend < 0.001), with an average difference of approximately 460 kJ/d for men and 365 kJ/d for women, between categories of the Cambridge index. The EPIC-PAQ is suitable for categorizing European men and women into four distinct categories of overall physical activity. The difference in PAEE between categories may be useful when estimating effect sizes from observational research.

Place, publisher, year, edition, pages
Dordrecht: Springer Netherlands, 2012
Keyword
Physical activity, Validity, Self-report, Questionnaire, Accelerometry
National Category
Environmental Health and Occupational Health Public Health, Global Health, Social Medicine and Epidemiology
Identifiers
urn:nbn:se:umu:diva-53812 (URN)10.1007/s10654-011-9625-y (DOI)000301184300003 ()
Available from: 2012-04-04 Created: 2012-04-04 Last updated: 2012-04-04Bibliographically approved
2. Computed tomography-based validation of abdominal adiposity measurements from ultrasonography, dual-energy X-ray absorptiometry and anthropometry
Open this publication in new window or tab >>Computed tomography-based validation of abdominal adiposity measurements from ultrasonography, dual-energy X-ray absorptiometry and anthropometry
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2010 (English)In: British Journal of Nutrition, ISSN 0007-1145, E-ISSN 1475-2662, Vol. 104, no 4, 582-588 p.Article in journal (Refereed) Published
Abstract [en]

Large-scale aetiological studies of obesity and its pathological consequences require accurate measurements of adipose mass, distribution and subtype. Here, we compared the validity of three abdominal obesity assessment methods (dual-energy X-ray absorptiometry (DXA), ultrasound and anthropometry) against the gold-standard method of computed tomography (CT) in twenty-nine non-diseased middle-aged men (BMI 26.5 (sd 3.1) kg/m(2)) and women (BMI 25.5 (sd 3.2) kg/m(2)). Assessments of adipose mass (kg) and distribution (total subcutaneous (TSAT), superficial subcutaneous (SSAT), deep subcutaneous (DSAT) and visceral (VAT)) were obtained. Spearman's correlations were performed adjusted for age and sex. VAT area that was assessed using ultrasound (r 0.79; P < 0.0001) and waist circumference (r 0.85; P < 0.0001) correlated highly with VAT from CT, as did BMI (r 0.67; P < 0.0001) and DXA (r 0.70; P < 0.0001). DXA (r 0.72; P = 0.0004), BMI (r 0.71; P = 0.0003), waist circumference (r 0.86; P < 0.0001) and ultrasound (r 0.52; P = 0.015) were less strongly correlated with CT TSAT. None of the comparison measures of DSAT was strongly correlated with CT DSAT (all r approximately 0.50; P < 0.02). BMI (r 0.76; P < 0.0001), waist circumference (r 0.65; P = 0.002) and DXA (r 0.75; P < 0.0001) were all fairly strongly correlated with the CT measure of SSAT, whereas ultrasound yielded a weaker yet statistically significant correlation (r 0.48; P = 0.03). Compared with CT, visceral and subcutaneous adiposity can be assessed with reasonable validity using waist circumference and BMI, respectively. Ultrasound or DXA does not generally provide substantially better measures of these traits. Highly valid assessments of DSAT do not appear to be possible with surrogate measures. These findings may help guide the selection of measures for epidemiological studies of obesity.

Keyword
Computed tomography, Ultrasound, Waist circumference, Waist:height ratio, Dual-energy X-ray absorptiometry, Obesity, Adipose tissue, Validation
Identifiers
urn:nbn:se:umu:diva-35681 (URN)10.1017/S0007114510000796 (DOI)20370942 (PubMedID)
Available from: 2010-08-31 Created: 2010-08-31 Last updated: 2011-05-26Bibliographically approved
3. Estimation of daily energy expenditure in pregnant and non-pregnant women using a wrist-worn tri-axial accelerometer
Open this publication in new window or tab >>Estimation of daily energy expenditure in pregnant and non-pregnant women using a wrist-worn tri-axial accelerometer
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2011 (English)In: PLoS ONE, ISSN 1932-6203, Vol. 6, no 7, e22922- p.Article in journal (Other academic) Published
Abstract [en]

Background Few studies have compared the validity of objective measures of physical activity energy expenditure (PAEE) in pregnant and non-pregnant women.  PAEE is commonly estimated with accelerometers attached to the hip or waist, but little is known about the validity and participant acceptability of wrist attachment. The objective of the current study was to assess the validity of a simple summary measure derived from a wrist-worn accelerometer (GENEA, Unilever Discover, UK) to estimate PAEE in pregnant and non-pregnant women, and to evaluate participant acceptability.

 

Methods  Non-pregnant (N=73) and pregnant (N=35) Swedish women (aged 20–35 yrs) wore the accelerometer on their wrist for 10 days during which total energy expenditure (TEE) was assessed using doubly-labelled water. PAEE was calculated as 0.9 x TEE - REE. British participants (N=99; aged 22–65 yrs) wore accelerometers on their non-dominant wrist and hip for seven days and were asked to score the acceptability of monitor placement (scored 1 [least] through 10 [most] acceptable).

 

Results There was no significant correlation between body weight and PAEE. In non-pregnant women, acceleration explained 24% of the variation in PAEE, which decreased to 17% in leave-one-out cross-validation. In pregnant women, acceleration explained 11% of the variation in PAEE, which was not significant in leave-one-out cross-validation. Median (IQR) acceptability of wrist and hip placement was 9(8-10) and 9(7-10), respectively; a within-individual difference of 0.47 was significant (p<.001).

 

Conclusions A simple summary measure derived from a wrist-worn tri-axial accelerometer adds significantly to the prediction of energy expenditure in non-pregnant women and is scored acceptable by participants.

Identifiers
urn:nbn:se:umu:diva-43893 (URN)10.1371/journal.pone.0022922 (DOI)21829556 (PubMedID)
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-08-24Bibliographically approved
4. Physical activity, sedentary behaviors, and estimated insulin sensitivity and secretion in pregnant and non-pregnant women
Open this publication in new window or tab >>Physical activity, sedentary behaviors, and estimated insulin sensitivity and secretion in pregnant and non-pregnant women
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2011 (English)Other (Other academic)
Abstract [en]

Aims Overweight and obesity during pregnancy raise the risk of gestational diabetes and birth complications. Lifestyle factors such as physical activity may decrease these risks through beneficial effects on systemic glucose homeostasis. Here we examined physical activity patterns and their relationships with measures of glucose homeostasis in late pregnancy compared to non-pregnant women.

Methods Normal weight and overweight women without diabetes (N=108; aged 25-35 years) were studied; 35 were pregnant (in gestational weeks 28-32) and 73 were non-pregnant. An oral glucose tolerance test was conducted from which insulin sensitivity and β-cell response were estimated. Physical activity was measured during 10-days of free-living using a combined heart rate sensor and accelerometer. Total (TEE), resting (REE), and physical activity (PAEE) energy expenditure were measured using doubly-labeled water and expired gas indirect calorimetry.

Results Total activity (counts/day) was associated with a reduced first-phase insulin response in both pregnant (r=-0.47; 95% CI: -0.70- to -0.15) and non-pregnant women (r=-0.36; 95% CI: -0.56- to -0.12). Pregnant women were estimated to have secreted more insulin (p=0.002) and had lower fasting glucose than non-pregnant women (p<0.0001). Measures of overall

physical activity intensity were similar in both groups (p=0.547), but pregnant women spent more time sedentary (p<0.0001), less time in moderate-to-vigorous intensity activity (p<0.0001), had lower objectively measured total activity, and had lower physical activity energy expenditure (PAEE) than non-pregnant women (p=0.045).

Conclusions Our findings suggest that physical activity conveys similar benefits on glucose homeostasis in pregnant and non-pregnant women, despite differences in subcomponents of physical activity.

Identifiers
urn:nbn:se:umu:diva-43894 (URN)
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-05-26Bibliographically approved
5. Metabolic risk-factor profiles in infants in relation to those of their mothers during pregnancy
Open this publication in new window or tab >>Metabolic risk-factor profiles in infants in relation to those of their mothers during pregnancy
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2011 (English)Other (Other academic)
Abstract [en]

Background Maternal characteristics during pregnancy such as BMI, weight gain, and glucose tolerance have been associated with anthropometric traits in their offspring. Here we extend these observations looking at the associations between maternal body composition, weight gain by trimester, and glucose tolerance and anthropometrics in their infants.

Materials and methods Participants were 31 (16 female) singleton babies and their mothers (aged 25-35 yrs) in the eastern area of the county of Västerbotten in Sweden. Maternal weight was measured at gestational weeks 10-12, 28-32, and 37-41. Maternal body composition was assessed using isotope dilution and gestational glucose tolerance was assessed with a 2-hour, 75-gram oral glucose challenge at 28-32 weeks gestation. Infant body composition was assessed at 11-19 weeks of age using air- displacement plethysmography. The relationships between maternal and infant variables were assessed with Spearman correlations.

Results Mid-pregnancy weight gain was significantly positively related to fat mass (r=0.41, p= 0.022) but not fat-free mass whereas late-pregnancy weight gain was significantly positively related to infant fat-free mass (r=0.37, p=0.04) but not fat mass. Maternal weight, body composition, or glucose tolerance was not significantly related to infant body composition. Early infancy growth (weight-for-length growth z-score) from 0 to 4 months was significantly related to infant percent fat (r=0.48, p=0.006). Gestational weight gain by trimester is differently related to body composition assessed in early infancy. Additionally, greater early infancy growth is associated with higher percent fat at 4 months of age. Both of these findings might identify targets for interventions conducted in pregnancy and during early life.

Identifiers
urn:nbn:se:umu:diva-43896 (URN)
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-05-26Bibliographically approved

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