Albertine J. Schuit

Reproducibility and relative validity of the Short Questionnaire to Assess Health-enhancing physical activity

BACKGROUND/OBJECTIVES The purpose of this study is to determine reproducibility and relative validity of the Short QUestionnaire to ASsess Health-enhancing physical activity (SQUASH). METHODS Participants (36 men and 14 women, aged 27-58) were asked to complete the SQUASH twice with an inbetween period of approximately 5 weeks. In addition, participants wore the Computer Science and Applications (CSA) Activity Monitor for a 2-week period following the first questionnaire. RESULTS The Spearman correlation for overall reproducibility of the SQUASH was 0.58 (95%-CI 0.36-0.74). Correlations for the reproducibility of the separate questions varied between 0.44 and 0.96. Spearmans correlation coefficient between CSA readings and the total activity score was 0.45 (95%-CI 0.17-0.66). CONCLUSIONS In conclusion, the SQUASH is a fairly reliable and reasonably valid questionnaire and may be used to order subjects according to their level of physical activity in an adult population. Because the SQUASH is a short and simple questionnaire, it may proof to be a very useful tool for the evaluation of health enhancing physical activity in large populations.

Validity of the Physical Activity Scale for the Elderly (PASE): according to energy expenditure assessed by the doubly labeled water method.

The study investigates the validity of the Physical Activity Scale for the Elderly (PASE) in 21 Dutch elderly men and women. The PASE is an easily scored, brief questionnaire for elderly, suitable for large epidemiologic studies. The PASE score was compared with physical activity measured with the doubly labeled water method. The correlation coefficient of the PASE score with the residuals from the regression analysis using total energy expenditure as dependent and resting metabolic rate as independent variate was 0.58 (95% CI = 0.50-0.81). Women had greater engagement in extremely high scoring activities as housework and taking care of others, resulting in higher PASE scores than men (97.9 and 71.9). The higher scores in women were not linked to higher activity levels, which suggests that the mentioned activities may be overvalued. Sex specific correlation coefficients were 0.79 (CI = 0.32-0.95) and 0.68 (CI = 0.15-0.90) for men and women, respectively. In conclusion, the PASE proved to be a reasonable valid method to classify healthy elderly men and women into categories of physical activity. Some possible refinements were suggested, which may improve the accuracy of the PASE questionnaire.

Disagreement in physical activity assessed by accelerometer and self-report in subgroups of age, gender, education and weight status

BackgroundThe purpose of this study is to compare self-reported time (by questionnaire) and objectively measured time (by accelerometer) spent on physical activity at moderate (MPA) and vigorous intensity (VPA) in subgroups of age, gender, education and weight status.MethodsIn total, 236 adolescents (aged 12–18) and 301 adults (aged 22–40), completed the questionnaire and wore an accelerometer for two weeks.ResultsAdolescents reported exceptionally more time spent on MPA (mean difference 596 ± 704 min/wk) and VPA (mean difference 178 ± 315 min/wk) than was assessed objectively by the accelerometer. Based on the questionnaire, high educated adolescents spent more time on MPA (205 min/wk, p = 0.002) and VPA (120 min/wk, p = 0.01) than low educated adolescents, but according to the accelerometer they spent less time on MPA (149 min/wk, p = 0.001) and VPA (47 min/wk, p = 0.001). Among adults there was moderate agreement between self-reported time and objectively measured time spent on MPA, but in general the reported time spent on MPA (mean difference 107 ± 334 min/wk) and VPA (mean difference 169 ± 250 min/wk) exceeded the time measured with the accelerometer. Overweight adults reported significantly more VPA (57 min/wk, p = 0.04) than normal weight adults, but this was not confirmed by the accelerometer data.ConclusionWe observed large differences in time spent on MPA and VPA measured by questionnaire and accelerometer in adolescents but reasonably good agreement in adults. Differences between methods varied by gender, education and weight status. This finding raises serious questions about the use of questionnaires to quantify MPA and VPA in adolescents. There is a clear need in advanced valid assessments of PA in adolescents.Trial numberISRCTN93896459

Reliability and validity of the Activity Questionnaire for Adults and Adolescents (AQuAA)

BackgroundAccurate measures of physical activity are highly needed. We evaluated the test-retest reliability and construct validity of the self-report Activity Questionnaire for Adults and Adolescents (AQuAA). The AQuAA is a commonly used questionnaire in Dutch youth.MethodsIn the test-retest reliability study, 53 adolescents and 58 adults completed the AQuAA twice, with an interval of two weeks. In the validity study, 33 adolescents and 47 adults wore an accelerometer (Actigraph) during two weeks, and subsequently completed the AQuAA.ResultsIn adolescents the test-retest reliability was fair to moderate (intraclass correlations (ICCs) ranging from 0.30 to 0.59). In adults the test-retest reliability was fair to moderate for the time spent on sedentary, light and moderate intensity activities (ICCs ranging from 0.49 to 0.60), but poor for time spent on vigorous activities (ICC = -0.005). The correlations between the AQuAA and Actigraph were low and nonsignificant. Compared with the Actigraph, time spent on all physical activities was significantly higher according to the questionnaire (except for light intensity activities in adolescents), while time spent on sedentary behaviours was significantly lower.ConclusionReliability of the AQuAA is fair to moderate. The validity of the AQuAA compared to an accelerometer is poor. Both adolescents and adults underestimate the time spent on sedentary behaviours and overestimate the time spent on physical activities.

Price discounts significantly enhance fruit and vegetable purchases when combined with nutrition education: a randomized controlled supermarket trial

BACKGROUND Reducing fruit and vegetable (F&V) prices is a frequently considered policy to improve dietary habits in the context of health promotion. However, evidence on the effectiveness of this intervention is limited. OBJECTIVE The objective was to examine the effects of a 50% price discount on F&Vs or nutrition education or a combination of both on supermarket purchases. DESIGN A 6-mo randomized controlled trial within Dutch supermarkets was conducted. Regular supermarket shoppers were randomly assigned to 1 of 4 conditions: 50% price discounts on F&Vs, nutrition education, 50% price discounts plus nutrition education, or no intervention. A total of 199 participants provided baseline data; 151 (76%) were included in the final analysis. F&V purchases were measured by using supermarket register receipts at baseline, at 1 mo after the start of the intervention, at 3 mo, at 6 mo (end of the intervention period), and 3 mo after the intervention ended (9 mo). RESULTS Adjusted multilevel models showed significantly higher F&V purchases (per household/2 wk) as a result of the price discount (+3.9 kg; 95% CI: 1.5, 6.3 kg) and the discount plus education intervention (+5.6 kg; 95% CI: 3.2, 7.9 kg) at 6 mo compared with control. Moreover, the percentage of participants who consumed recommended amounts of F&Vs (≥400 g/d) increased from 42.5% at baseline to 61.3% at 6 mo in both discount groups (P = 0.03). Education alone had no significant effect. CONCLUSIONS Discounting F&Vs is a promising intervention strategy because it resulted in substantially higher F&V purchases, and no adverse effects were observed. Therefore, pricing strategies form an important focus for future interventions or policy. However, the long-term effects and the ultimate health outcomes require further investigation. This trial was registered at the ISRCTN Trial Register as number ISRCTN56596945 and at the Dutch Trial Register (http://www.trialregister.nl/trialreg/index.asp) as number NL22568.029.08.

Effect of Exercise on Postmenopausal Sex Hormone Levels and Role of Body Fat: A Randomized Controlled Trial

PURPOSE To examine the effects of a 1-year exercise intervention on sex hormone levels in postmenopausal women and whether any effects are mediated by changes in body fat composition. METHODS We randomly assigned 189 sedentary postmenopausal women (age 50 to 69 years, body mass index of 22 to 40 kg/m(2)) to an exercise intervention (n = 96) or a control group (n = 93). The intervention combined aerobic and strength training and comprised supervised group sessions and home-based exercises (a total of 2.5 h/wk). Between-group differences in sex hormone levels (at baseline and 4 and 12 months) were examined with generalized estimating equations. RESULTS In total, 183 women (97%) completed the study. Overall, the exercise intervention did not result in favorable effects on sex hormone levels. Among women who lost more than 2% body fat, declines in all estrogens were not significantly different between exercisers and controls. Androgen levels decreased significantly in the exercise group who lost body fat compared with their peers in the control group. Furthermore, this study confirmed that fat loss was significantly associated with declines in postmenopausal estrogen levels. Although not significant, a similar trend was observed for the androgens. CONCLUSION This study confirms that fat loss is associated with changes in postmenopausal sex hormone levels and suggests that exercise may be effective in inducing favorable changes in these hormones.

Validity of the Modified Baecke Questionnaire: comparison with energy expenditure according to the doubly labeled water method

BackgroundIn epidemiological research, physical activity is usually assessed by questionnaires. Questionnaires are suitable for large study populations since they are relatively inexpensive and not very time consuming. However, questionnaire information is by definition subjective and prone to recall bias, especially among elderly subjects. The Modified Baecke Questionnaire, developed by Voorrips and coworkers, measures habitual physical activity in the elderly. The questionnaire includes questions on household activities, sports, and leisure time activities, over a time period of one year. The Modified Baecke Questionnaire results in a score to classify people as high, moderate, or low in daily physical activity, based on tertiles.MethodsThe validity of the Modified Baecke Questionnaire score was assessed among 21 elderly men and women using the doubly labeled water method as the reference criterion. This method is considered to be the gold standard for measuring energy expenditure in free-living individuals. Energy expenditure on physical activity is estimated by the ratio of total energy expenditure measured by the doubly labeled water method and resting metabolic rate measured by indirect calorimetry. This ratio is called the physical activity ratio.ResultsThe Spearman correlation coefficient between the questionnaire score and the physical activity ratio (PAR) was 0.54 (95% CI 0.22–0.66). Correct classification by the questionnaire occurred in 71% of participants who were in the lowest tertile of PAR, in 14% of participants in the middle tertile, and in 43% of participants in the highest tertile. Subjects were not wrongly classified in an opposite tertile.ConclusionThe validity of the Modified Baecke Questionnaire is fair-to-moderate. This study shows that the questionnaire can correctly classify individuals as low or high active, but does a poor job for moderately active individuals.

Introducing taxes, subsidies or both: The effects of various food pricing strategies in a web-based supermarket randomized trial

OBJECTIVE Fiscal policies may form a solution in improving dietary intake. This study aimed to examine the effectiveness of varying taxing and subsiding schemes to stimulate healthier food purchases. METHODS A randomized controlled trial with three levels of price reduction on healthy foods (no; 25%; 50%)×three levels of price increase on unhealthy foods (5%; 10%; 25%) factorial design was used. 150 participants were randomized into one of nine conditions and were asked to purchase groceries at a web-based supermarket. Data were collected in the Netherlands in January-February 2010 and analyzed using analysis of covariance. RESULTS Subjects receiving 50% discount purchased significantly more healthy foods than subjects receiving no (mean difference=6.62 items, p<0.01) or 25% discount (mean difference=4.87 items, p<0.05). Moreover, these subjects purchased more vegetables (mean difference=821 g;p<0.05 compared to no discount). However, participants with the highest discount also purchased significantly more calories. No significant effects of the price increases on unhealthy foods were found. CONCLUSION Price decreases are effective in stimulating healthy food purchases, but the proportion of healthy foods remains unaffected. Price increases up to 25% on unhealthier products do not significantly affect food purchases. Future studies are important to validate these results in real supermarkets and across different countries.

Feasibility and Effectiveness of Online Physical Activity Advice Based on a Personal Activity Monitor: Randomized Controlled Trial

Background Inactive people are often not aware of the fact that they are insufficiently active. Providing insight into their actual physical activity (PA) levels may raise awareness and could, in combination with tailored PA advice, stimulate a physically active lifestyle. Objective This study evaluated the feasibility and effectiveness of a 3-month intervention in which Dutch office workers were provided with a personal activity monitor (PAM) coupled to simple and concise Web-based tailored PA advice (PAM COACH). Method Participants were randomly assigned to the 3-month PAM intervention (n = 51) or received a single written information brochure with brief general PA recommendations (n = 51). Study outcome measures were changes in PA (recall of minutes per week spent on PA, as measured by the Activity Questionnaire for Adolescents and Adults), determinants of PA, aerobic fitness, and body composition. Follow-up measurements were performed immediately after the 3-month intervention and at 8-months, 5 months after the end of the 3-month intervention period. Results A total of 102 workers, 23 to 39 years old, completed the baseline measurement at the worksite. 48 completed the 3-month follow up and 38 the 8-month follow-up in the intervention group, 50 completed the 3-month follow up and 42 the 8-month follow up in the control group. 35 out of 48 (73%) participants in the PAM intervention group reported wearing the PAM regularly, and the PAM COACH was used almost once a week; 24 out of 46 (52%) PAM users set a personal goal, and 33 (72%) entered their favorite activities on the website. Main reasons for not using these items were lack of interest or not being able to find the item on the website. The majority of PAM users (34 out of 46, 74%) read the advice, of whom 14 (39%) found it unappealing. After the 3-month intervention, no significant intervention effect was observed (adjusted difference in min/week) for sedentary behavior (β = 10, 95% CI = −435 to 455), light-intensity PA (β = −129, 95% CI = −337 to 79), moderate-intensity PA (β = −13, 95% CI = −89 to 63), vigorous-intensity PA (β= −6, 95% CI = −75 to 62), and moderate- to vigorous-intensity PA (β = −23, 95% CI = −121 to 76). No significant intervention effect was observed in the PA outcomes at the 8-month follow-up. For the determinants of PA, aerobic fitness, and body composition, no statistically significant intervention effect was observed in the total study population immediately after the 3-month intervention or the 8-month follow-up. Conclusions The intervention appeared to be easily applicable to real-life settings. The intervention was ineffective in improving PA behavior or its determinants in healthy office workers. More attention should have been given to the quality and appropriateness of the tailored advice. Trial Registration International Standard Randomized Controlled Trial Number (ISRCTN): 93896459; http://www.controlled-trials.com/ISRCTN93896459/ (Archived by WebCite at http://www.webcitation.org/5iR3mf7ex)

Concurrent validity of the PAM accelerometer relative to the MTI Actigraph using oxygen consumption as a reference

The purpose of this study was to examine the concurrent validity of the Personal Activity Monitor (PAM) accelerometer relative to the Actigraph accelerometer using oxygen consumption as a reference, and to assess the test–retest reliability of the PAM. Thirty‐two fit, normal weight adults (aged 21–54) performed two activities, treadmill walking and stair walking, while wearing the PAM, the Actigraph and the Cosmed K4b2. Correlation coefficients and agreement in absolute energy expenditure (EE) levels between PAM, Actigraph and Cosmed were calculated. The test–retest reliability was examined among 296 PAMs using a laboratory shaker. Intraclass correlation coefficients (ICC) and coefficient of variation (CV) were determined. Correlations for treadmill walking and stair walking, respectively, were r2=0.95 and r2=0.65 for PAM with Actigraph, r2=0.82 and r2=0.93 for PAM with VO2 and r2=0.64 and 0.74 for Actigraph with VO2. Both the PAM and Actigraph underestimated EE during treadmill and stair walking by a substantial amount. The test–retest reliability of the PAM was high [ICC=0.80; 95% confidence interval (CI) (0.28;0.92) and intra‐CV=1.5%]. The PAM and Actigraph accelerometer are comparable in assessing bodily movement during treadmill and stair walking. The PAM is a valid device to rank subjects in EE and can be useful in collecting objective data to monitor habitual physical activity.