Use of the Pregnancy Physical Activity ... - Semantic Scholar

Journal of Physical Activity and Health, 2013, 10, 1000-1007 © 2013 Human Kinetics, Inc.

Official Journal of ISPAH www.JPAH-Journal.com ORIGINAL RESEARCH

Use of the Pregnancy Physical Activity Questionnaire (PPAQ) to Identify Behaviors Associated With Appropriate Gestational Weight Gain During Pregnancy Tamara R. Cohen, Hugues Plourde, and Kristine G. Koski Background: The Pregnancy Physical Activity Questionnaire (PPAQ) assesses physical activity practices of pregnant women. The purpose of this study was to identify specific pregnancy practices that were associated with a healthy gestational weight gain (GWG). Methods: Associations between PPAQ scores, pedometer steps, energy intakes (EI), energy expenditures (EE), and rate of GWG were assessed for 61 pregnant women in their second or third trimester during a home visit. Principle component analyses (PCA) were used to cluster PPAQ questions into Factors associated with either rate or total GWG, physical activity (PA), EE, EI, and parity. Results: PCA identified 3 Factors: Factor 1 associated EE with parity and child care; Factor 2 clustered several structured exercise activities; and Factor 3 grouped walking, playing with pets, and shopping with pedometer steps. Only Factor 3 clustered steps with weekly rate of GWG. EI was not associated with PA or GWG. Conclusions: PCA analysis identified 15 of 32 PPAQ questions that were related to increased physical activity in pregnant women, but only walking and pedometer steps were associated with GWG. Our analysis supports daily walking as the preferred PA for achieving a healthy rate of GWG. Keywords: pedometer, steps, metabolic equivalents, nutrition It is established that pregnant women with uncomplicated pregnancies should engage in 30–40 minutes of regular physical activity 3–4 times per week.1,2 Physical activity (PA) during pregnancy does not only provide the excellent cardiovascular effects of aerobic training, but also reduces the risks of gestational diabetes, hypertensive disorders3 and plays a role in prevention of preterm labor.4 In addition to activity guidelines, there also exist dietary5 and gestational weight gain recommendations1 that should be encouraged by health professionals and followed by all pregnant women as excessive weight gain during pregnancy can lead to obesity related comorbidities.6 Physical activity assessment tools, such as accelerometer and pedometers, have been promoted as effective objective methods of assessing PA during pregnancy.7–15 As walking is the most common form of activity during pregnancy,16 pedometers are considered a practical tool for use during pregnancy,8,10,12,17–20 and can be used in conjunction with subjective tools such as questionnaires.21 Currently there are 4 validated questionnaires for the pregnant population.9,13,14,21 Notwithstanding these questionnaires, the short nature and user-friendly approach of

the Pregnancy Physical Activity Questionnaire (PPAQ) is of particular interest not only to researchers who wish to examine current or changes in PA practices of women but important for prenatal care providers who wish to address PA with expecting mothers.9,10,22 Although models that explore pregnancy behaviors have shown that PA impacts’ GWG, it remains unclear what types or intensities of activities are correlated with optimal pregnancy outcomes, such as healthy gestational weight gain (GWG). The purpose of this study was to use the statistical method of principle component analysis (PCA) to determine the interrelationships among PPAQ questions, energy intakes and expenditures, pedometer steps, and gestational weight gain. Unlike regression analysis that assumes independence between variables, PCA allows for analysis of variables that may be highly correlated with one another, and clusters highly correlated variables as “principle components.” The purpose of this study was to use PCA to identify those PPAQ questions that were associated with specific pregnancy variables and outcomes.23

Methods Participants

The authors are with the School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada.

1000

This study was approved by the McGill University Research Ethics Board (Montreal, QC), Ottawa Public Health Reproductive Unit (Ottawa, ON) and various

PPAQ Behaviors and Gestational Weight Gain 1001

Montreal (QC) Health and Social Service Centers. As previously described,24 women were recruited from public prenatal classes, where English and French presentations were conducted to inform participants of the study. Inclusion criteria were for women in their second and third trimesters without contraindications to exercise as per the PARMed-X for Pregnancy.25

Study Procedure Women were visited at home, where they were weighed using a Tanita Digital scale and completed the bilingual Pregnancy Physical Activity Questionnaire (PPAQ).9 Women wore the Digiwalker Pedometer SW-200 (Yamax Corp, Japan) and completed a pedometer logbook for 1 week. Other original data collected included sociodemographic questions adopted from the Canadian Community Health Survey26 and telephone dietary recalls. Considered as a standard measurement time point used to evaluate the magnitude of weight gain during pregnancy,27,28 women were phoned to obtain their current weight and total gestational weight gain as recorded by their physician at their routine 6-week postpartum visit.

The Pregnancy Physical Activity Questionnaire The PPAQ is a validated, self-administered questionnaire that takes on average 10–15 minutes to complete, and has been used to assess the current physical activity levels of pregnant women. 9 This questionnaire is composed of 32 questions, grouped into different types of activities [ie, household/care giving (13 questions), occupational (5 questions), sports/exercise (8 questions), transportation (3 questions), and as well as inactivity (3 questions)].2 Specifically, the semiquantitative questionnaire asked women to estimate the duration and frequency spent per activity (ie, “none,” “less than 1/2 hour per day,” “1/2 to almost 1 hour per day,” “1 to almost 2 hours per day,” “2 to almost 3 hours per day,” “3 or more hours per day”) during the current 1 month. Women were not asked about specific durations, but rather acknowledged the time spent performing an activity by checking-off the appropriate duration (time) presented in the PPAQ as a range. Women were also given the opportunity to provide 2 activities that were not listed on the questionnaire. These intensities were individually estimated using the Compendium of Physical Activity.29 Specific scoring of the questionnaire was provided by those authors who granted permission to use the PPAQ. In brief, an estimated average metabolic equivalent (MET-hr/wk) value was calculated using the duration of the time spent in each activity multiplied by the established categorical intensity value associated with the question. Activities were categorized by intensity (ie, light, moderate, vigorous), type (ie, household, occupation, sport), or as total activity (sum of all intensity and type scores).9 According to the Joint SOGC/ CSEP Clinical Practice Guidelines for Exercising during

Pregnancy,2 we estimated that women should achieve 8.5 MET-hr/wk to meet these recommendations.24 Previous work has shown that achieving the 8.5 MET-hr/wk is associated with healthy GWG.24

Pedometer The pedometer model used in this study was the NewLifestyle Digiwalker SW-200 (NL SW-200; Oregon). The NL SW-200 has been tested with the pregnant population12 and has been used in other pregnancy studies.10 The NL SW-200 is a small, light-weight pedometer that comes with a safety clip and only measures steps. All our participants completed the 20-walk step test daily and were instructed during the home visit how to properly place the pedometer, as pedometer sensitivity changes with an increased waist circumference thus affecting pedometer accuracy.30 Women were asked to wear the pedometer for 7 days starting the next day, recording daily steps before bed and resetting the device in the morning. Women were instructed to remove the pedometer for bathing, swimming and sleeping only. Once finished with the record keeping for 1 week, women returned the logbooks by mail to the researchers and were allowed to keep their pedometers. Pedometer steps were expressed as mean steps/day and categorized as sedentary: < 5000 steps/day; low active: 5000–7499 steps/day; active: > 7500 steps/day.31 The results from the pedometer (steps/day) were not used to estimate energy expenditure (EE).

Other Measures Postpartum assessment included average rate of weight gain (kg/week) and total gestational weight gain (kg). Our dietary recalls were performed by telephone interviews. During the home visit, women were provided with instructions on how to complete the dietary interviews that would be conducted randomly by telephone. Specifically, women were called during 1 weekend and 2 weekdays at a time that was convenient for them but they did not know which day they would be phoned. These 24-hour dietary recalls were performed within 1 week of the home visit, using the multipass technique. Telephone-administered dietary recalls are a valid method of assessing mean nutrient intakes in all populations.32 The interviewers were trained and knowledgeable about foods available in the marketplace, preparation practices and regional and ethnic foods. Mean energy intake (EI; kcal) and macronutrient distribution (% protein, % carbohydrate, % fat) were analyzed using the Canadian Nutrient File 200733 and ESHA Research Food Processor (version 9.1; Salem, OR). Average daily EE was calculated using the PPAQ, following this equation: [(Sum of PPAQ total MET-hr/week) × (3.5 mLO2/kg/min) × (60 min/hour) × (body weight (kg))] to yield a value in mLO2/week.6 Converting this value to liters and multiplying it by 5 kcal/L divided by 7 days/ week resulted in an estimated average daily EE.6

1002 Cohen, Plourde, and Koski

Statistical Analysis All data were analyzed using Statistical Analysis Software (Version 9.2, 2002–2003, SAS Institute Inc., Cary, NC) and PASW Statistics 18 (SPSS Inc., Chicago, IL). Pearson correlation coefficients (95% confidence intervals) were calculated comparing pedometer steps, sociodemographic, GWG assessment variables against PPAQ results. Principle component analysis (PCA) was used to explore possible linear relations among all study variables (ie, PPAQ questions, dietary analyses, sociodemographic variables, pedometer steps and GWG), which permitted those variables of interest that were interrelated to be reduced into Factors. Unlike regression analysis that assumes independence between variables, PCA allows for analysis of variables that may be associated with one another. The communality, or the degree of variation between each identified Factor, was set at ≥ 0.3. Statistical significance was set at < 0.05 for all tests.

Results Population Characteristics Of the 142 women approached, a total of 81 consented to participate in the study, of which 61 completed all phases of the study and were included in this analysis. Mean age ranged between 30.0–34.9 years with 70% classified as having normal prepregnancy BMI. Most were first time mothers (80%) with household incomes > $50,000/year and with university educations (67%). Women participated once in their second [n = 29, mean 21.1 weeks (range: 15–26)] or third [n = 32, mean 32.3 weeks (range: 27–38)] trimester. Rates of weight gain ranged widely with women either losing (–0.3 kg/week) or gaining (1.9 kg/week) weight. Most women exceeded the recommended rate of GWG of 0.4 kg/week for normal prepregnancy BMI as per the Institute of Medicine recommendations.1 On average, women were expending 2451 ± 956 kcals/day, and were consuming appropriate macronutrient distributions, averaging 2247 ± 484 kcals/day. Women reported participating in mostly light intensity (1.5–2.9 METs; mean 79.8 ± 41.2 MET-hr/week) activity in the form of occupation-type activities (mean 96.5 ± 62.9 MET-hr-week). Pedometer step analyses classified women as “low active” (mean 5843 ± 2203 steps/day; Table 1). However, PA did not differ between trimesters: pedometer steps (T2: 5981 ± 2087 steps/day; T3: 6242 ± 2301steps/day) and total MET-hr/week (T2: 417.2 ± 146.2 MET-hr/wk; T3: 363.71 ±152.43 MET-hr/wk). Correlation analyses were used to assess associations between the PPAQ, average daily steps (pedometer), sociodemographic variables, gestational weight gains and energy balance (EI and EE; Table 2). Positive correlations were found between the pedometer and total PPAQ (r = .36, P = .01), light and moderate intensity (r = .26, P = .04 and r = .27, P = .04 respectively) and occupational activities (r = .26, P = .04). Some but not

all sociodemographic variables correlated with PPAQ intensity and type scores. Education was negatively correlated with PPAQ (total r = –0.28, P = .03), moderate (r = –0.33, P = .01), and occupational activity (r = –0.34, P = .01)), while parity was positively correlated with light intensity activities (r = .27, P = .04), specifically household/care giving (r = .56, P = .001) type activities. Only the proportion of energy from protein was negatively correlated with sedentary activity (r = –0.35, P = .01) whereas total MET-hr/wk, light intensity, household and occupational activities were positively correlated with EE (Table 2). Transportation-type PA was not performed by most women; 70% reported either none or less than one-half hour per day.

Principle Component Analysis The principle component analysis (PCA) identified relationships that existed among variables, clustering them together into 3 Factors (Table 3). The PCA explained a cumulative variance of 53.3%, and included 15 PPAQ questions from all intensity ranges (7 light intensity, 7 moderate intensity, 1 vigorous intensity) and all types (8 household, 3 sport/exercise, and 1 occupation). Dietary intake variables were not significant. Specifically, Factor 1 (eigenvalue 4.2; 22.3% variance) loaded 7 variables, including parity, energy expenditure and 5 PPAQ questions related to caregiving activities of which 60% were performed at moderate and 40% at light intensities. Factor 2 (eigenvalue 3.8; 20.2% variance) loaded 7 PPAQ questions that included both household and prenatal exercise classes as well as several individual sport/exercise activities performed at all intensity levels. Unique from other factors, Factor 3 (eigenvalue 2.1; 10.9% variance) included pedometer steps and rate of weight gain (kg/ week) in addition to purposeful walking. Specifically, this Factor included 3 PPAQ questions such as playing with pets (PPAQ question 14), walking slowly for fun or exercise (PPAQ question 23) and shopping (PPAQ question 16).

Discussion The purpose of this study was to identify specific questions from the PPAQ that were associated with other pregnancy variables, including EI, EE, and PA (steps and PPAQ questions), and gestational weight gain. Using PCA, 3 Factors emerged showing interrelationships for 15 of the 32 PPAQ questions. Only walking as part of daily living, and not questions related to structured physical activity or prenatal exercise classes, was associated with a women’s weekly rate of weight gain. In no model did EI or total GWG emerge as significant. However, Factor 3 clustered both walking and pedometer steps with weekly rate of gestational weight gain, strongly indicating that pregnant women who engaged in purposeful walking routines associated with activities of daily living can achieve healthy weekly rates of weight gain.


Table 1 Descriptive Analysis of Subject’s Weight Gain, Nutrition, and Physical Activity Scores Pregnancy assessment Rate of weight gain (kg/wk) Energy intake Total energy (kcal/day) Protein (% total energy) Carbohydrate (% total energy) Fat (% total energy) Energy expenditure Total energy (kcal/day) Physical activity habits Pedometer steps (steps/day) Pregnancy Physical Activity Questionnaire Total MET-hr/week Sedentary activity MET-hr/week Intensity score Light activity MET-hr/week Moderate activity MET-hr/week Vigorous activity MET-hr/week Type score Household/caregiving MET-hr/week Occupational MET-hr/week Sports/exercise MET-hr/week Transportation MET-hr/week

Mean

Minimum

25%

50%

75%

Maximum

SD

0.7

–0.3

0.5

0.7

0.9

1.9

0.4

2247.0 16.5 53.7 31.9

1079.5 10.6 39.5 19.4

1906.4 13.6 49.2 27.4

2232.7 16.4 53.4 32.2

2577.1 18.9 58.6 34.6

3762.9 26.7 71.5 47.2

484.5 3.1 7.3 6.6

2451.8

764.7

1917.1

2198.7

2927.8

5768.2

956.8

6132.5

844.6

4562.9

5843.3

7830.4

11,089.3

2202.9

224.2

58.2

177.8

216.9

260.4

445.8

76.2

84.8

16.5

62.7

90.7

104.5

138.3

28.3

79.8

13.4

43.3

79.4

114.4

173.5

41.2

58.7

0.0

21.5

40.4

74.1

250.1

56.7

1.8

1.0

1.0

1.0

1.0

10.8

1.8

60.8

8.1

29.0

43.2

82.0

202.5

47.5

96.5

0.0

67.2

86.5

119.2

298.2

62.9

6.1

0.0

2.4

3.7

8.2

36.2

6.8

146.3

0.0

39.9

110.4

220.2

929.2

162.1

Our PCA analyses also identified 2 other Factors comprising mostly light and moderate intensity activities in the form of household/caregiving and light-intensity sport activities. These results support others who have shown that pregnant women still spend more than 50% of their physical activity time engaged in household or caregiving activities.9,13 However in our study, neither of these 2 groups of activities was sufficient to modulate rates of gestational weight gain, leaving us with the recommendation that all pregnant women of all body mass index classifications should incorporate walking into their daily routine to achieve a fit pregnancy.34 These results support others who have suggested walking during pregnancy as a means to manage

gestational weight gain.24,35 Walking has been reported as the most popular type of activity practiced during pregnancy16 as it is easily incorporated into daily routines in a nonstrenuous way. Furthermore, as research has established that exercise practices decline as pregnancy progresses,36,37 walking can be maintained by most women throughout pregnancy. However, only 30% of our study participants met adult steps recommendations for active living,24 indicating that the majority of women were sedentary despite continuing occupational and household/ caregiving activities. Currently, pregnant women are encouraged to engage in moderate intensity activities for 30 minutes or more a day on most days of the week.2 Although

1004

–0.28* 0.11 –0.13 –0.33* –0.04 0.04 –0.34* 0.08

–0.20 0.03 –0.15 –0.17 –0.19 0.05 –0.23* –0.13

0.26* 0.27* 0.11 0.12 0.26* 0.22

Age

0.25* –0.04 –0.08

0.06 –0.01 –0.09

0.08 0.15

0.56* 0.03 0.02

0.27* –0.20 0.15

–0.22 0.20

Sociodemographic variables Total Mothers University income with education >$50,000 children

0.36* 0.03

* P ≤ .05. Abbreviations: GWG, Gestational weight gain.

PPAQ (MET-hr/week) Total activity Sedentary Intensity score Light Moderate Vigorous Type score Household/care giving Occupational Sports/exercise

Pedometer (steps/day)

Activity

–0.16 0.09 –0.02

–0.12 –0.02 0.05

–0.06 0.02

0.00 –0.01 –0.16

0.18 –0.18 –0.02

–0.02 .005

Pregnancy assessment Total Rate of GWG GWG (kg/week) (kg)

0.02 0.03 –0.04

–0.06 0.11 –0.13

0.08 0.09

0.46* 0.63* 0.24

0.73* 0.63 0.17

0.87* 0.01

Energy balance Energy Energy intake expenditure (kcal/day) (kcal/day)

Table 2 Correlation Between Pregnancy Assessment Variables (Steps, Demographic, and Weight Gain) Against Pregnancy Physical Activity Questionnaire Total, Intensity, and Type Scores (MET-hr/week)


Table 3 Three Factor Solution Using the Principle Component Method Based on PPAQ Questions, Objective Physical Activity Assessment, and Pregnancy Outcome Variables Factor 1 Factor 1: Caregiving PPAQ #6 Dressing, bathing, feeding children while standing PPAQ #7 Playing with children while sitting of standing PPAQ #8 Playing with children while walking or running Parity PPAQ #5 Dressing, bathing, feeding children while sitting PPAQ #9 Carrying children Energy expenditure (kcal) Factor 2: Active living PPAQ #31 Yoga PPAQ #27 Prenatal exercise class PPAQ #17 Heavier cleaning PPAQ #25 Walking quickly up hills PPAQ #33 Standing or slowing walking at work carrying things PPAQ #30 Strength training PPAQ #15 Light cleaning Factor 3: Walking as part of daily living PPAQ #14 Playing with pets PPAQ #23 Walking slowly for fun or exercise Pregnancy Assessment Mean pedometer steps (steps/day) Pregnancy Outcome Rate of weight gain (kg/wk) PPAQ #16 Shopping (for food, clothes, or other items) Eigenvalues % of the variance

some suggest that vigorous or structured type of sport/ exercise routines should be the primary prescription for pregnant women,6,8,9,37,38 our analyses showed that more structured exercise programs that included prenatal exercise classes, yoga, or strength training and even walking quickly up a hill, which is categorized as moderate intensity, sport/exercise activity, were not associated with appropriate GWG. Therefore, our PCA supports the notion that promoting vigorous activity to sedentary pregnant women may not be the first step to achieve recommended GWG. Rather, the message may be for sedentary pregnant women to engage in physical activities that accumulate more than 6000 steps per day in nonstructured routines. The later could be accomplished with the recommendation for pregnant women to wear a pedometer.24 Despite some limitations to using pedometers, such as accuracy changes over fixed distances,39 and speeds40 and differences that occur between models, 12,39,40 pedometers have been successfully promoted to pregnant women18,19,24 in research studies even though targets may not have been set.

Factor 2

Factor 3

0.837 0.829 0.823 0.814 0.747 0.653 0.521 0.879 0.723 0.722 0.714 0.702 0.625 0.592

4.23 22.28%

3.83 20.16%

0.688 0.674 0.594 0.519 0.425 2.07 10.89%

We provide the following cautions when interpreting our results. The EE calculations presented in this paper are approximations since the duration of each activity is classified as a categorical-duration variable in the PPAQ. Therefore, we lack a true continuous measure of PA (ie, the MET-hr/wk). Moreover, we only measured PA once during either second or third trimester, and were unable to stratify by trimester when analyzing data by PCA because the Kaiser-Meyer-Olkin (KMO) was very small (0.6).23 Because of the power of our study, we were unable to see differences in PA between the 2 trimesters, which also prevented us from analyzing our PCA analysis by trimester. Larger studies are warranted. Given that the average rate of weight gain in our study population was nearly twice the Institute of Medicine’s recommendation, it is surprising that the self-reported values for both EE and EI yielded a small difference of 200 kcal; however, this would result in GWG approaching the values reported in this study. Consequently, if women walked for approximately 20 minutes per day, this daily discrepancy would be inconsequential and would likely not lead to weight gain from an energy imbalance.

1006 Cohen, Plourde, and Koski

Conclusions In conclusion, this study showed important interrelationships among specific PPAQ questions that measured walking as part of daily activities, pedometer steps and the rate of gestational weight gain. These results suggest that the PPAQ should be used as an easy method of assessing current physical activity practices in pregnant women with uncomplicated pregnancies. Since walking as part of daily living was related to rate of GWG, simple walking routines should be encouraged during pregnancy. The PPAQ may be useful to include in standard prenatal care as it can help providers adjust regimens, guide interventions and may be used when counseling women about PA and appropriate gestational weight gains. Our analyses identified specific PPAQ questions that could be used in routine clinical care to promote PA in pregnant women.

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