|
 
 |
| ORIGINAL ARTICLE |
|
| Year : 2014 | Volume
: 14
| Issue : 2 | Page : 121-127 |
|
The association between physical activity, overweight and obesity among Syrian University students
Louay Labban
Department of Nutrition and food Science, Faculty of Health sciences, University of Kalamoon, Damascus, Syria
| Date of Web Publication | 9-Oct-2014 |
Correspondence Address:
Louay Labban
University of Kalamoon 30440, Damascus
Syria
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/1319-6308.142366
Obesity and being overweight are considered as global health problems because obesity increases the risk of several chronic diseases such as cardiovascular disease (CVD) and diabetes. Physical activity plays an important role in preventing overweight and obesity in young people and stemming its progression into young adulthood. Adolescence is a particularly vulnerable time for the development of obesity because it is marked by a slowing of growth and corresponding decrease in physical activity levels. In addition, physically active youth have lower levels of adiposity than youth who are less active. Several studies have identified the role of physical activity in attaining a healthy body weight. A study carried out at the University of Kalamoon, revealed that the prevalence of overweight and obesity in Syria is almost 47%. The objective of this study was to find out the association between physical activity, overweight and obesity in Syrian university students. An accurate assessment of physical activity is important in determining the risk of overweight and obesity. The absence of local and national relevant data in the Arab world could pose challenges to epidemiological studies on physical activity in these countries. Data from the International Physical Activity Questionnaires (IPAQ) short format on 320 Syrian university students (age 18-26) were analyzed. The prevalence of overweight/obesity had a strong inverse association with physical activity among males and females alike but was more visible in females. The low intensity and short duration of the physical activity has also played a role in shigher body mass index (BMI) values. More metabolic equivalent of tasks (METs) minutes/week resulted in lower BMI values and on the contrary, sitting time had a positive relationship with higher BMI values. There was a significant difference (P < 0.05) between males and females with regard to METs minutes/week which was 4854 ± 1272 and 4408 ± 1136 for males and females respectively in the normal weight group and for 4368 ± 984 and 4041 ± 985 for males and females, respectively in overweight group and 3385 ± 982 and 3063 ± 801 for males and females, respectively in obesity group. This trend also applies to sitting METs minutes/week. In the normal weight group, males had higher values than females whereas females had higher values in the overweight and obesity group but thedifference was significant (P < 0.05) between males and females in the three groups. These results underscore the importance of promoting physical activity among adolescence to prevent and control overweight and obesity. العلاقة بين النشاط البدني و فرط الوزن و البدانة بين طلاب الجامعة السورية
تعدّ البدانة و فرط الوزن من المشكلات الصحّيةّ العامّة ؛ لأن البدانة تزيد كثيرا من مخاطر الإصابة بالأمراض المزمنة مثل أمراض القلب و الأوعية الدموية و السكري .و بالمقابل فإن النشاط البدني يؤدي دورا مهمّا في الوقاية من زيادة الوزن و البدانة لدى الشباب و الناشئة في مرحلة المراهقة خاصة .فتقل معدلات البدانة عند الشباب الذين يمارسون النشاط البدني و تزيد معدلات البدانة عند الذين ينخفض نشاطهم و يتباطأ نموهم . و قد أثبتت كثير من الدراسات دور النشاط البدني في الحصول على وزن صحي مثالي. ومن تلك الدراسات دراسة أجريت في جامعة القلمون (سوريا) بهدف معرفة العلاقة بين النشاط البدني وفرط الوزن و البدانة في طلاب الجامعة ؛ حيث كشفت أن معدل انتشار زيادة الوزن و البدانة في سوريا يقارب 47 ٪. و بما أن التقييم الدقيق للنشاط البدني مهم في تحديد مخاطر فرط الوزن و البدانة ؛ فإن غياب البيانات المحلية و الإقليمية في الوطن العربي يشكل تحديا للدراسات في هذه البلدان. و قد تم تحليل البيانات بأستعمال الاستبانات العالمية للنشاط البدني (IPAQ) ل 320 طالبا سوريا تراوحت أعمارهم بين 18 26 سنة وقد أظهرت النتائج أن لزيادة الوزن و البدانة علاقة عكسية بالنشاط البدني عند الذكور والإناث على حدّ سواء ، إلاّ أن العلاقة كانت أكثر وضوحا في الإناث . كما لعب النشاط الفيزيائي منخفض الحدة وقصر فترة النشاط البدني دورا في أرتفاع قيم مؤشرات كتلة الجسم BMI . و كذلك فإن معدلات أعلى للتكافؤ الأيضي (METs) دقيقة/بالاسبوع أدت الى أنخفاض قيم مؤشر كتلة الجسم BMI . و كان لانخفاض حدة النشاط البدني و قصرمدّته دورا في أنخفاض قيم مؤشر كتلة الجسم BMI. وعلى العكس من ذلك فأن زيادة أوقات الجلوس كان لها علاقة في زيادة قيم BMI .
و قد كانت هنالك فروقات ذات دلالة احصائية P<0.05 بين الذكور والإناث في مؤشر كتلة الجسم بالنظر إلى الجهد البدني (METs) دقيقة/بالاسبوع حيث كانت 4854±1272 و 4408±1136للذكور والنساء على التوالي في مجموعة الوزن الطبيعي و 4368±984 و 4368±984 و 4041±985 لدى الذكور والاناث في مجموعة زيادة الوزن على التوالي و 3385±982 و 3063±801 للذكور والاناث في مجمعة البدانة على التوالي. وينطبق هذا الاتجاه على المكافئ الايضي المصروف خلال أوقات الجلوس (دقيقة/بالاسبوع). حيث كان في أعلى عند الذكور مفارنة مع الاناث في مجموعة الوزن الطبيعي بينما كان أعلى عند الاناث في مجموعة زيادة الوزن والبدانة مقارنة مع الذكور ولكن كان الفرق والاناث معنويا في المجموعات الثلاث (P<0.0.5) . و هذا الاتجاه ينطبق على مجموعة الوزن ± 982 و 3063 ± الإناث لمجموعة الوزن الثقيل و 3385الزائد. و في مجموعة الوزن العادي يحظى الذكور بقيم دلالية أكبر من الإناث كما أن للإناث قيم دلالية أكبر في الأوزان الزائدة و حالات بين الذكور و الإناث في المجوعات الثلاث . p< البدانة على أن الفروق كانت ذات دلالة احصائية 0.05 وهذه النتائج توضح أهمية تشجيع النشاط البدني بين المراهقين للوقاية من الوزن الزائد و البدانة و مخاطرهما. توضح هذه النتائج أهمية تشجيع النشاط البدني بين المراهقين للوقاية وتدبير الوزن الزائد و البدانة و مخاطرهما
Keywords: Adolescent, body mass index, Damascus, International Physical Activity Questionnaires, metabolic equivalent of tasks, physical activity, obesity, overweight, University of Kalamoon
How to cite this article:
Labban L. The association between physical activity, overweight and obesity among Syrian University students. Saudi J Sports Med 2014;14:121-7 |
How to cite this URL:
Labban L. The association between physical activity, overweight and obesity among Syrian University students. Saudi J Sports Med [serial online] 2014 [cited 2023 Jun 10];14:121-7. Available from: https://www.sjosm.org/text.asp?2014/14/2/121/142366 |
| Introduction | |  |
Overweight and obesity are considered a global epidemic by the World Health Organization. [1]
Physical activity plays an important role in preventing the development of overweight and obesity in young people and stemming its progression into young adulthood. Adolescence is a particularly vulnerable time for the development of obesity because it is marked by a slowing of growth and corresponding decrease in physical activity levels. [2] A significant proportion of adolescents do not meet recommended physical activity guidelines. [3] In addition, physically active youth have lower levels of adiposity than youth who are less active. [4] There is a much higher risk of overweight adolescents becoming overweight adults.
Several epidemiological and intervention studies [5] and [6] have identified the role of physical activity and physical fitness for overweight children and adolescents, and hence we focused on the role of sport during leisure time. O'Dea 2007 provided an overview of studies on the relationship between physical activity and overweight and also between fitness and overweight in children or adolescents. Despite the influence of physical activity and fitness on health outcomes including overweight, till date results of studies on the interaction between all three parameters have not been synthesized since these parameters cannot be considered independently. [7] In addition, most reviews omitted studies on adolescents and young adults or did not include longitudinal studies.
Several studies have proved that performing physical activities on a regular basis (at least 30 minutes a day of moderate intensity physical activity) improves life quality and health status and prevent and control cardiovascular diseases, hypertension, diabetes, obesity, etc. [8]
According to WHO estimates, up to 80% of diabetes cases and cardiovascular diseases and up to 30% of some types of cancer (WHO 2003) could be avoided by establishing preventive interventions such as improvement of diet quality and physical activity.
At the national level, there is no information about practice levels of physical activity in adults. There is also no information based on large-scale population studies in Syria on the association between physical activity practice and overweight and obesity. Hence, this study aimed at documenting the levels of physical activity and evaluated the relationship between physical activity and overweight/obesity in Syrian university students in order to design strategies and interventions that help prevent and control this public health problem.
The purpose of this study was to estimate the prevalence of overweight and obesity among Syrian University students and to examine the relationship between physical activity and overweight and obesity in adolescents, and to identify the interrelationship among these three parameters particularly considering gender differences because of the significant differences in these parameters between male and female students.
Definitions
Physical activity comprises all modes of movement caused by muscle activity resulting in increased energy expenditure. [9]
Overweight and obesity are defined as abnormally high fat content that may impair health and as high bodyweight (exceeding the standard measure) caused by an increased fat consumption. [1]
| Materials and methods | | |
The study was carried out at the university of Kalamoon in Dier Attiah city in Damascus countryside.
The study used the English version of short the International Physical Activity Questionnaires (IPAQ) on a sample of 320 participants (165 males and 155 females) aged 18 to 26 years selected at random. All participants were living in the University's dormitories at the time of the survey. Participants who were underweight (body mass index, BMI <18.5) and those who were incapable of performing physical activity were excluded from the study.
Each volunteer was separately interviewed by the principal investigator for their understanding of the content of the questionnaire, the clarity of each item, and their opinion and suggestions for improvement. They were also asked to indicate if any question made them feel uncomfortable and if any relevant items were not included in the questionnaire.
The IPAQ collects information on the time (i.e., number of days and average time per day) spent being physically active and the intensity of this activity (vigorous, moderate, walking or sitting) and then translated into metabolic equivalent of tasks (METs) minutes per week. [10]
Vigorous physical activity was defined as a group of activities requiring energy expenditure equal or higher than 6 METs/hour (physical activity energy expense unit). This category included activities such as aerobics, fast bicycle riding, lifting weights, running for long distance, or activities that involve more difficult breathing than normal.
Moderate physical activity was defined as a group of activities requiring less energy expenditure (between 3.0 and 5.9 METs/hour); such as lifting light objects or riding a bicycle at regular speed. It did not include walking. Time spent walking was classified into a different category and included walking in the campus, from one place to another, or walking during leisure time, for sports, exercise or pleasure for periods of time of at least 10 minutes.
Sedentary activities or low physical activity that require less energy expenditure were also defined, such as time students spent sitting at class or at home studying, watching TV, or resting.
MET's minutes/week was calculated according to Bushman 2012. [11]
Data were collected between March and June 2011 by trained interviewers supervised by the author. Objectives, procedures, risks and benefits of the study were explained in detail to every potential participant. The protocol for this study was approved by the department's council.
Overweight or obesity was based on BMI (weight in kilograms/height in meters 2 ). Anthropometric measurements were taken by trained individuals. Weight and fat percentage were measured with Tanita, Japan (Scale and electronic impedance machine). Weight was measured to 100 g accuracy. The same machine was also used to determine fat percentage. Height was measured with Stadiometer (Seca 217, United Kingdom) with capacity for 2 meters and accuracy to 1 mm.
The participants were classified according to their nutrition status using the cutoff points recommended by the WHO 2003 for BMI as follows: underweight (BMI < 18.5), normal weight (BMI from 18.5 to 24.9), overweight (BMI from 25.0 to 29.9), and obesity (BMI > 30.0). BMI values less than 15 and over 58 kg/m 2 were not considered as valid values.
Descriptive data were reported as mean, standard deviation and percentages. Mean group differences in physical activity (minutes/week) by gender were examined by independent t-test. Data were entered and analyzed using Statistical Package for the Social Science (SPSS), version 15.0 for windows (SPSS Inc., Chicago, Illinois, USA) and the level of significance was set at P < 0.05.
| Results | | |
Three hundred and twenty students participated in this study which consisted of 165 males (51.6%) and 155 females (48.4%). Males had a higher BMI than females. The average BMI of males was 27.7 ± 16.54 and that of females was 26.7 ± 15.98.
Females had more individuals with normal weight when compared with their male counterparts. Ninety two females or 59.4% had normal weight compared to 49 males or 29.7% had normal weight and the difference was significant (P < 0.05). Males had a higher percentage of overweight and obese individuals compared to females. Total of 78 males (47.3%) were overweight and 38 (23%) were obese and, in total, 116 males (70.3%) were overweight and obese. With regard to females, 41 females (26.5%) were overweight and 22 (14.1%) were obese. In total, 73 females (40.6%) were overweight and obese. There was a significant difference between males and females in overweight and obese group (P < 0.05).
The participants were also divided into two groups based on their age. The majority of the participants were in the age group 18-22 years. In this group, there were 232 participants (72.5%) and 88 participants (27.5%) were in the age group 23-26 years.
The average BMI of the normal group in males was 21.8 ± 2.74 and in females 19.9 ± 5.36. The difference was significant at P < 0.05. In the overweight group, males had a BMI average of 28.1 ± 3.28 and females had 27.8 ± 5.98. Obese males had higher BMI average than obese females. BMI average of males was 33.2 ± 4.11 and females 32.5 ± 6.75, there was no significant difference between BMI averages in overweight and obese males and females (P < 0.05).
Females had higher average of fat percentage when compared with males in the three BMI groups. In the normal weight group, males had 12 ± 3.44% of fat and females had 26.6 ± 6.48% whereas in overweight and obese groups, males had 17 ± 3.78% and 24 ± 5.48% and females had 36 ± 11.43% and 39 ± 14.29%, respectively. Only males and females had a healthy range of fat percentage in the normal weight group whereas males and females had higher than normal fat percentage in overweight and obese groups. [12]
There was a significant difference between males and females in the three BMI groups with regard to fat percentage (P < 0.05). The results are shown in [Table 1].
Data collected from this study present descriptive information for physical activity. Although males had higher percentage of overweight and obesity but their mean METs minutes/week for vigorous physical activity was greater than in females (2990 ± 1654 and 2659 ± 1647, respectively) and for moderate physical activity (1747 ± 1541 and 1610 ± 1186, respectively). Mean METs minutes/week for walking was 1390 ± 1221 for males and 1139 ± 947 for females, and for sitting time, it was 1020 ± 865 for males and 1009 ± 864 for females. In the overweight group (BMI 25-29.9), males had higher means of vigorous, moderate and walking time (METs minutes/week). Males spent 2788 ± 1476 and females spent for the same intensity exercise 2485 ± 1562 whereas time spent on moderate exercise and walking for males was 1578 ± 1498 and 1312 ± 1198 and for females was 1464 ± 974 and 1092 ± 918 respectively. Also, obese males spent more time on vigorous, moderate and walking time when compared with females. Males spent 2205 ± 1521, 1450 ± 1176 and 1130 ± 1078 and females spent 1190 ± 879, 1090 ± 866 and 1002 ± 854 for vigorous, moderate and walking times respectively.
According to data on men's nutrition status, the greatest proportion of overweight/obesity was found in those aged 22 to 26 years (79%). Obese males had less METs minutes/week physical activity (vigorous, moderate, and walking) and remained sitting for a longer time compared with males with adequate BMI. Most males in the low physical activity category were overweight or obese, compared with men with adequate BMI (21.1% and 17.6%, respectively). As for the high physical activity category, the greatest proportion corresponded to males with adequate BMI compared with overweight or obese males (63.7% and 61.6%, respectively).
With reference to females, the greatest proportion of overweight/obesity was found in those aged 21 to 26 years (49%) indicating that younger females are more active and there is some kind of relationship between age and obesity. Overweight females had less METs minutes/week of vigorous physical activity and of those walking compared with females whose BMI were normal.
Likewise, obese females had much less METs minutes/week of moderate and vigorous physical activity and reported more sitting time, compared with females whose BMI was adequate. The majority of females in the low and high physical activity categories were those with obesity (33.3%), compared with females whose BMI was normal and with those with overweight as demonstrated in [Table 2]. | Table 2: Mean METs (minutes/week) according to BMI values for different intensity exercise
Click here to view |
On the other hand, according to the IPAQ, significant associations between overweight/obesity and the physical activity practice categories were found in males.
With regard to normal BMI, most of the males (63.7%) were in the high physical activity category, 15.2% in the moderate physical activity and 21.1% in the low physical activity. There were more females with normal BMI, which as per this study showed that 73.1% were in high intensity and 14.6% and 12.3% for moderate and low physical activity, respectively. In overweight group, 61.6% of the males performed vigorous exercise compared to 54.5% of females for the same BMI value. 20.8% and 17.6% of the males in overweight group performed moderate and low intensity exercise respectively, and 25.2% and 20.3% of the females performed the same level of exercise in overweight group.
In the obese group, it is very clear that the percentage of males and females performing vigorous exercise is declining. On the contrary, proportion of males and females in this group performing low intensity exercise in on the increase and this explains the inverse relationship between exercise intensity and BMI value. The results are summarized in [Table 3]. | Table 3: Physical activity categories percentages (according to IPAQ in METs minutes/week)
Click here to view |
[Figure 1] shows a comparison between males and females according to their BMI values with regards to time spent (hours/day) on different types of exercise intensity such as moderate, vigorous walking and sitting times.
Results obtained from this study have showed that males spent more time on total physical activity (moderate and vigorous) and walking comparing with females. Males who had normal BMI spent a total of 11.6 hours/day doing various physical activities like walking, moderate and vigorous physical activity whereas females with same BMI group spent 10.5 hours/day doing the same activities and the difference between males and females was significant (P = 0.04). In the overweight group, males spent 10.4 hours/day and females 9.6 hours/day performing different types of physical activities and the difference was not significant (P = 0.05) but in the obese group the difference between males and females was significant (P = 0.04) because males spent 8.1 hours/day and females 7.4 hour/day. The results are shown in [Table 4] and [Figure 2]. | Table 4: Total time (hours/day) spent on various physical activities and walking for males and females according to their BMI
Click here to view |
 | Figure 2: Comparison of total time spent on various physical activities of males and femails according to their BMI
Click here to view |
The previous table showed that BMI values are inversely related to total time spent on physical activity (Walking-moderate and vigorous) but directly related with sitting time. More sitting time resulted in higher BMI values for both males and females. These results are corresponding with the findings of other studies [13],[14] .
Surprisingly, sitting time was equal in males and females for the normal weight group and there was no significant difference since both groups who had 4.8 hours/day sitting times. In overweight group, females had more sitting time than males for the same group. Females had 7.1 and males had 6.2 hours/day and the difference was significant (P = 0.04). This also applies to obese group. Females had 8.4 hours/day whereas their male counterparts had 7.1 hours/day sitting time and the difference was significant (P = 0.04) as shown in [Figure 3]. | Figure 3: Comparison of sitting times between males and females according to their BMI
Click here to view |
| Discussion | | |
The results of this study have shown that physical activity was inversely associated with the prevalence of overweight/obesity in a representative sample of Syrian university students. Such association was observed among males and females. This is the first study, to our knowledge, documenting this finding in a nationwide probabilistic sample of Syrian adolescents of both sexes.
Little physical activity in females, particularly vigorous and moderate, may account for that effect on the association. There also exists the possibility of overestimation of physical activity in women with overweight/obesity, as has been documented in other studies [15] and [16] The results obtained from this study are in total agreement with a previous study by Lichtman S et al.[17] in which he found an inverse association between the intensity of physical activity and the prevalence of overweight and obesity and sitting times were directly related to overweight and obesity.
The results are plausible given the observed trend towards decrease in physical activity owing to the sedentary nature of many work activities, the changes in transportation methods and sprawling urbanization. In addition, the increase of energy-rich foods, rich in fat and sugar, has brought about an imbalance between intake and energy expenditure. [18] Also, physical activity was measured through the IPAQ questionnaire, an internationally validated instrument for measuring physical activity in individuals 18 to 26 years old, which can be used in prevalence studies based on national populations. As a standard indicator, the IPAQ questionnaire is recommended for making comparisons within a country, between countries, and worldwide.
This study has some limitations that should be considered for being not representative of the whole country. However, this information is valuable as it documents the association between physical activity and overweight/obesity and helps to identify groups that perform less physical activity (particularly intense physical activity in females, as has been documented in other studies). [19] This underscores the necessity of focusing interventions on that population group to promote physical activity. In conclusion, physical activity was inversely associated with overweight/obesity in a representative sample of Syrian university students both males and females. Therefore, encouraging vigorous or moderate physical activity and reducing sedentary activities, along with the promotion of a healthy diet, are necessary steps aimed at preventing and controlling overweight/obesity in both adolescents, thus decreasing the risk of chronic diseases in those population groups.
| References | | |
| 1. | World Health Organization. Report of a Joint WHO/FAO Expert Consultation. Diet Nutrition and the Prevention of Chronic Diseases. WHO Technical Report Series 916. Geneva: WHO; 2003.  |
| 2. | Stankov I, Olds T, Cargo M. Overweight and obese adolescents: What turns them off physical activity? Int J Behav Nutr Phys Act 2012;9:53. |
| 3. | Brodersen NH, Steptoe A, Boniface DR, Wardle J. Trends in physical activity and sedentary behavior in adolescence: Ethnic and socioeconomic differences. Br J Sports Med 2007;41:140-4. |
| 4. | Tremblay MS, Willms JD. Is the Canadian childhood obesity epidemic related to physical inactivity? Int J Obes Relat Metab Disord 2003;27:1100-5. |
| 5. | O'Dea JA. Improving the eating behaviors of children and adolescents: Are we neglecting the crucial role of parents? Nutrition Dietetics 2005;62:66-8. |
| 6. | Deforche B, De Bourdeaudhuij I, Tanghe A, Debode P, Hills AP, Bouckaert J. Post-treatment phone contact: A weight maintenance strategy in obese youngsters. Int J Obes (Lond) 2005;29:543-6. |
| 7. | In: Ritchie J, Lewis J, editors. Qualitative Research Practice: A Guide for Social Science Students and Researchers. London: Sage Publications; 2003. |
| 8. | Manson JE, Skerrett PJ, Greeland P, VanItallie TB. The escalating pandemics of obesity and sedentary lifestyle. A call to action for clinicians. Arch Intern Med 2004;164:249-58. |
| 9. | Jackicic JM, Polley BA, Wing RR. Accuracy of self-reported exercise and the relationship with weightloss in overweight women. Med Sci Sports Exerc 1998;30:634-8. |
| 10. | Irwin ML, Ainsworth BE, Conway JM. Estimation of energy expenditure from physical activity measures: Determinants of accuracy. Obes Res 2001;9:517-26. |
| 11. | Bushman BA. How can I use METS to quantify the amount of aerobic exercise? ACSM's Health Fitness J 2012;16:5-7. |
| 12. | Vella CA, Kravitz L. Gender differences in fat metabolism. IDEA Health and Fitness Source 2002;20:36-46. |
| 13. | Morales-Ruán Mdel C, Hernández-Prado B, Gómez-Acosta LM, Shamah-Levy T, Cuevas-Nasu L. Obesity, overweight, screen time and physical activity in Mexican adolescents. Salud Publica Mex 2009;51:S613-20. |
| 14. | Mahabir S, Baer DJ, Giffen C, Clevidence BA, Campbell WS, Taylor PR, et al. Comparison ofenergy expenditure estimates from 4 physical activity questionnaires with doubly labeled water estimates in postmenopausal women. Am J Clin Nutr 2006;84:230-6. |
| 15. | Trout J, Graber K. Perceptions of overweight students concerning their experiences in physical education. J Teach Phys Educ 2009;28:272-92. |
| 16. | Alm M, Sordoudi N, Wylie-Rosett J, Isasi CR, Suchday S, Rieder J, et al. A qualitative assessment of barriers and facilitators to achieving behavior goals among obese inner-city adolescents in a weight management program. Diabetes Educ 2008;34:277-84. |
| 17. | Lichtman SW, Pisarska K, Berman ER, Pestone M, Dowling H, Offenbacher E, et al. Discrepancy between self-reported and actual caloric intake and exercise in obese subjects. N Engl J Med 1992;327:1893-8. |
| 18. | Booth M. Assessment of physical activity: An international perspective . Res Q Exerc Sport 2000;71:114-S20. |
| 19. | Hernández B, de Haene J, Barquera S, Monterrubio E, Rivera J, Shamah T, et al. Factors associated with physical activity among Mexican women of childbearing age. Rev Panam Salud Publica 2003;14:235-45. |
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]
|
Related articles