Workshop Report: Physical Activity and Cancer Prevention

Volume 21, No. 4 - 2000

[Table of Contents]

Workshop Report: Physical Activity and Cancer Prevention

Loraine D Marrett, Beth Theis, Fredrick D Ashbury and an Expert Panel

Volume 21, No. 4 - 2000

Abstract

A workshop to evaluate the evidence for the role of physical activity in cancer prevention and to identify priorities for action, particularly in relation to the primary prevention of cancer, was held by Cancer Care Ontario in March 2000. A review of the scientific evidence was commissioned and an expert panel convened to consider the review report and to make recommendations for public health, research and intervention. The panel concluded that evidence was convincing for the role of physical activity in preventing colon cancer; probable for breast cancer; possible for prostate cancer and insufficient for other sites. It recommended that physical activity messages promoting at least 30-45 minutes of moderate to vigorous activity on most days of the week be included in primary prevention interventions for cancer. The panel recommended that future research on physical activity incorporate comprehensive assessments, including measures of the multiple dimensions and types of physical activity; biological mechanisms; and behavioural and population factors. Cancer Care Ontario will incorporate physical activity messages in its primary prevention programming around nutrition and healthy body weight.

Key words: cancer etiology, cancer prevention, physical activity

Introduction

Cancer is the second ranking cause of death in Ontario after cardiovascular diseases. Unless cancer mortality rates decline as significantly as have those for cardiovascular diseases, it will likely become the leading cause of death within a few decades.¹

The National Cancer Institute of Canada estimates that 24,700 women and 25,200 men will be diagnosed with cancer and 11,200 women and 12,500 men will die from cancer in Ontario in the year 2000.² As the population grows and ages, and as techniques to detect cancer in its early stages are more systematically applied and improved, the number of people diagnosed with cancer will continue to rise. Health Canada's Cancer Bureau estimates that, if current trends continue, the number of new cancer cases will increase by 40% by the year 2010.³

The escalating cancer burden will increase the need for treatment services and will have serious repercussions for Ontario's health care system. A report by the Chief Medical Officer of Health for the Province of Ontario stated that some $1 billion was spent to treat persons with cancer in 1994 alone.⁴ Current costs are certainly higher because of the greater number of cases, and because the costs of some new chemotherapeutic agents are higher than those previously used. A diagnosis of cancer has serious personal financial consequences in the form of lost wages and the cost of medications to offset the symptoms of the disease and its treatments.

Cancer control encompasses prevention, early detection, treatment, supportive care, research and education. Although there have been impressive advances in the treatment of a few cancers, the four most common cancers (i.e., lung, breast, colon and prostate) have to date proved extremely difficult to treat effectively.⁵ To achieve important reductions in cancer incidence, morbidity and mortality, greater emphasis should be placed on prevention.⁶ Effective prevention initiatives can decrease cancer incidence and mortality by 50% or more.⁷

Rates of cancers of the colon, breast and prostate vary considerably around the world.⁸ For example, they are all much more common in North America than in Asia. These patterns and a large body of research support an important role for lifestyle factors in the etiology of these, as well as many other, types of cancer.

Identifying the role of physical activity in cancer prevention

In the fall of 1999, the Division of Preventive Oncology at Cancer Care Ontario (CCO) initiated a
two-step process to identify opportunities for research, policies and programs relating to physical activity and the primary prevention of cancer:

1. an expert in physical activity and cancer was commissioned to review, evaluate and summarize the evidence; and

2. a workshop of experts was convened to consider the review and to develop a consensus on the level of evidence and priorities for action.

CCO is a provincial cancer control agency responsible for the provision of many key cancer services and for overseeing all aspects of cancer control in Ontario. CCO's Division of Preventive Oncology is responsible for cancer prevention, screening and surveillance, research in preventive oncology and the Aboriginal cancer care program.

Review of the evidence for physical activity and cancer prevention

As a first step, CCO engaged Dr. Christine Friedenreich of the Alberta Cancer Board to conduct a systematic review of the published literature on the etiologic role of physical activity in relation to cancer.⁹ Dr. Friedenreich is a recognized expert in this field and is also familiar with the operational context of provincial cancer agencies. Her review included an assessment of the frequency, intensity and duration of physical activity associated with cancer risk reduction, a summary of physical activity intervention research, and her recommendations for further research and public health actions.

Dr. Friedenreich evaluated the evidence relating physical activity to a variety of cancers using an adaptation of the criteria described in the report by the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) on nutrition and cancer prevention.¹⁰ In this report, "convincing" evidence was defined as evidence that is conclusive; "probable" means that the evidence is strong enough to conclude that a causal relation was likely; "possible" means that a causal relation may exist; and "insufficient" means evidence is suggestive but too sparse to make a more definitive judgement. Table 1 presents more detailed descriptions of these levels of evidence.¹⁰

Dr. Friedenreich's report formed the basis of the workshop discussions. It was, however, expected that the participating experts' own knowledge of, and perspective on, both published and ongoing research would amplify and perhaps alter Dr. Friedenreich's conclusions and recommendations.

The workshop

The Physical Activity and Cancer Prevention workshop was held in Toronto on March 24-25, 2000. An expert panel was convened, comprising 11 scientists from academia, government and cancer agencies in Canada, the United States and Norway. Seven others were invited to attend as observers. See Appendix 1 for a list of participants, who represented the disciplines of epidemiology, physical education and health, exercise science and behavioural science.

Goal and objectives

The workshop's goal was to evaluate the evidence for the role of physical activity in preventing cancer. Its objectives were to achieve consensus on:

whether the epidemiological, biologic and intervention evidence on physical activity and cancer prevention is sufficiently strong to provide clear direction for public health recommendations and/or population interventions;
recommendations for further action (knowledge gaps to be addressed by research, types of research needed, public health recommendations, and/or interventions) according to cancer site (colorectal, breast, prostate, other sites); and
priority areas for further action.

Workshop materials, structure and agenda

Before the event, participants were sent the workshop agenda, a list of attendees, a copy of the report prepared by Dr. Friedenreich⁹ and published papers by two of the workshop participants in the specific areas of biologic mechanisms¹¹ and intervention research¹². During the workshop itself, selected additional information was distributed (e.g. Canadian data on population levels of physical activity; a summary of public health recommendations on physical activity from a variety of organizations).

A questionnaire intended to identify the workshop participants' perceptions of the state of the evidence (epidemiologic, biologic and intervention research) and to help identify public health issues and recommendations was also included in their pre-workshop packages. Participants were asked to submit their completed questionnaires to the facilitator before the event so that the responses could be collated for presentation early in the workshop. A copy of the pre-workshop questionnaire is appended to this report (Appendix 2).

The workshop agenda called for a full day to review, discuss, and begin to develop a consensus on the evidence. The second, shorter day was reserved for completing the development of the consensus and for developing public health recommendations supported by that evidence.

Discussion of the evidence

Workshop participants were given an orientation to the needs of CCO's Division of Preventive Oncology in the development of strategies on physical activity and cancer prevention. This was followed by the presentation of Dr. Friedenreich's report and of the pre-workshop questionnaire results. Table 2 summarizes Dr. Friedenreich's review of the epidemiologic literature and her evaluation of the strength of the evidence.

The presentations stimulated discussion on the quality of the epidemiologic evidence for various cancer sites and the potential for developing public health recommendations. This led to more focused discussion on possible biologic mechanisms for physical activity and cancer prevention and exercise intervention research.

Workshop findings

Consensus on the evidence

The workshop participants largely endorsed the conclusions of relationships between physical activity and cancer prevention presented in Dr. Friedenreich's review. The consensus on levels of evidence is outlined in Table 3.

TABLE 1 Description of levels of evidence^a
Level of evidence	Description
Convincing	Epidemiological studies show consistent associations, with little or no evidence to the contrary. There should be a substantial number of acceptable studies (more than 20), preferably including prospective designs, conducted in different population groups and controlled for possible confounding factors. Exposure data should refer to the time preceding the occurrence of cancer. Dose-response relationships should be supportive of a causal relationship. Associations should be biologically plausible. Laboratory evidence is usually supportive.
Probable	Epidemiological studies showing associations are either not so consistent, with a number of studies not supporting the association, or the number or type of studies is not extensive enough to make a more definite judgment. Mechanistic and laboratory evidence is usually supportive.
Possible	Epidemiological studies are generally supportive, but are limited in quantity, quality or consistency. There may or may not be supportive mechanistic or laboratory evidence. Alternatively, there are few or no epidemiological data, but strongly supportive evidence from other disciplines.
Insufficient	There are only a few studies, which are generally consistent, but really do no more than hint at a possible relationship. Often, more well-designed research is needed.
^a Descriptions are from the World Cancer Research Fund/American Institute for Cancer Research.¹⁰

TABLE 2 Summary of epidemiologic evidence on the association between physical activity and cancer^a
Cancer site	Consistency of evidence for a risk reduction with increased physical activity levels^b	Strength of risk association	Dose-response^c	Time of life	Biologic plausibility	Overall level of scientific evidence^d
Colon	42 of 48	up to 70%	21 of 31	Activity throughout life?	Yes - several possible mechanisms	Convincing
Breast	22 of 33	up to 70% to no effect	13 of 21	Early life? Adult life?	Yes - several possible mechanisms	Probable
Prostate	14 of 23	up to 50% to a 220%	9 of 17	Early life?	Yes - some possible mechanisms	Possible
Lung	7 of 10	60% to 30%	5 of 7	Unknown	Unclear	Insufficient
Testis	2 of 5	50% to no effect	2 of 4	Unknown	Unclear	Insufficient
Ovary	1 of 4	No effect	1 of 2	Unknown	Yes - a few possible mechanisms	Insufficient
Endometrium	7 of 11	90% to no effect	3 of 6	Unknown	Yes - a few possible mechanisms	Insufficient
^a Adapted from (9) and (13). ^b Number of consistent studies out of total studies, both case-control and cohort. ^c Number of studies with dose-response out of total studies. ^d See Table 1 for definitions.

TABLE 3 Consensus level of evidence for physical activity and cancer prevention
Cancer site	Level of evidence^a
Colon^b	Convincing
Breast	Probable
Prostate	Possible
Endometrium, lung, testis	Insufficient but promising for further investigation
Other	Insufficient
^a See Table 1 for descriptions ^b Many studies considered only colon and rectum cancers combined. However, there were enough studies on colon cancer alone to conclude that the evidence related to it, but not to rectal cancer, was convincing.

Public health recommendations

Table 4 presents the consensus public health recommendations for cancer risk reduction made to CCO by the workshop participants. The participants acknowledged the challenges of drawing definitive conclusions for public health recommendations from the available evidence; the scientific literature does not provide information on the details of level of physical activity required to achieve optimal benefit (i.e. duration, frequency, intensity, age). Despite these caveats, participants felt there was sufficient evidence to make responsible recommendations that were not inconsistent with those of other health bodies. Some examples are displayed in Table 5.

Research recommendations

Participants felt that more research was needed for the effects of physical activity on many cancer sites. All but one of the recommendations presented in Table 6 apply to studies of any cancer site. Because the evidence for the benefit of physical activity in colon cancer prevention is considered to be "convincing," participants identified the need to conduct intervention research of strategies to reduce colon cancer risk (see fifth-listed recommendation). The first recommendation is bolded to indicate that it represents a major overarching research consideration.

TABLE 4
Consensus public health recommendations on physical activity and cancer risk reduction

Physical activity recommendations should be included in primary prevention interventions for cancer prevention.

All messages for physical activity should be in the context of reducing the risk of cancer rather than preventing cancer.

In order to get cancer risk reduction benefits, physical activity should comprise at least 30-45 minutes of moderate to vigorous activity on most days of the week.

Examples of moderate and vigorous physical activities should be provided as part of messaging; these should include activities appropriate to various age, sex and cultural groups.

Messaging should recognize the variation in maximal cardiorespiratory capacity within the population. For example, since maximal capacity declines, on average, with increasing age, the upper end of the recommended activity level (i.e. 45 minutes of vigorous exercise) is in general more appropriate for youth and the lower end (i.e. 30 minutes of moderate exercise) for the elderly. Recommended activity levels for those who have been sedentary should initially be less than for those who are already active.

Physical activity messages can be linked to other risk reduction messages, such as maintaining a healthy body weight.

Physical activity should be encouraged at all ages.

Advocacy is required for policies and environmental supports for physical activity.

A surveillance and measurement system should be implemented for tracking population levels of physical activity.

TABLE 5 Summary of recommendations on physical activity from various organizations
Source	Recommendation^a
Health Canada/Canadian Society for Exercise Physiology (Canada's Physical Activity Guide)¹⁴	Get active your way, every day - for life. Scientists say accumulate 60 minutes of physical activity every day to stay healthy or improve your health. As you progress to moderate activities you can cut down to 30 minutes, 4 days a week. Add up your activities in periods of at least 10 minutes each. Start slowly . and build up.
Canadian Cancer Society (Seven Steps to Health)¹⁵	Be physically active on a regular basis. This will also help you maintain a healthy body weight.
Harvard Center for Cancer Prevention (7 ways to prevent cancer)¹⁶	Get at least 30 minutes of physical activity every day.
American Cancer Society (Guidelines on diet, nutrition and cancer prevention)¹⁷	Be at least moderately active for 30 minutes or more on most days of the week.
U.S. Dept of Health and Human Services (Healthy People 2000)¹⁸	Objective: Increase the proportion of people aged 6 and older who engage regularly, preferably daily, in light to moderate physical activity for at least 30 minutes per day to at least 30 percent.
U.S. Dept of Health and Human Services (Healthy People 2010)¹⁹	Objectives: Increase the proportion of adolescents who engage in vigorous physical activity that promotes cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion. Increase the proportion of adults who engage regularly, preferably daily, in moderate physical activity for at least 30 minutes per day.
International Union Against Cancer (UICC) (Statement on diet, nutrition and cancer)²⁰	Exercise to maintain weight.
World Cancer Research Fund/American Institute for Cancer Research¹⁰	If occupational activity is low or moderate, take an hour's brisk walk or similar exercise daily, and also exercise vigorously for a total of at least one hour a week.
^a Quoted directly from the referenced documents.

TABLE 6
Summary of research recommendations on physical activity and cancer prevention

Physical activity assessment should be comprehensive and include measures of
type, frequency, duration and intensity of physical activity in the relevant exposure periods (e.g. lifetime)
leisure, occupational, household and transportation forms of physical activity, in addition to other physical movements that require considerable energy expenditure (e.g. fidgeting)
biologic mechanisms (relevant to individual cancer sites and across cancer sites) and
behavioural and population (age, sex, socio-economic status, and culture) factors

Research should incorporate an assessment of the way physical activity relates to other factors, including obesity, diet, genetics and exposures such as use of medications, smoking and alcohol.

Studies should be conducted to establish biomarkers as intermediate endpoints in the pathway for the relationship between physical activity and cancer.

Intervention research is needed for colon cancer to determine the efficacy and effectiveness of various strategies to reduce risk.

Ongoing scans of published and current but unpublished physical activity research projects should be conducted to facilitate updating of assessment of evidence and public health recommendations.

Research is needed into environmental supports and policies needed to facilitate physical activity intervention implementation and adherence.

Qualitative research should be conducted to establish motivations to pursue a physically active lifestyle, with special attention to age, sex, socio-economic status, and culture.

Methodological research is needed on recall bias and the use of self-administered vs. interview-based data collection protocols for physical activity assessment.

Discussion

As the number of women and men diagnosed with cancer in Ontario (and throughout Canada) continues to rise, epidemiologic, biologic, behavioural and intervention research studies will be needed to facilitate public health interventions for lifestyle factors that can be modified to reduce an individual's risk of developing cancer. The process followed in the workshop enabled a thorough discussion of the existing evidence and afforded participants an opportunity to discuss and identify recommendations and priorities for public health and further research.

CCO has already incorporated this evidence assessment summary into its "Blueprint for Cancer Prevention in Ontario," which was released in May 2000.²¹ The Blueprint identifies tobacco control, promotion of healthy eating and physical activity as the organization's priorities for cancer prevention.

CCO is currently developing a program of risk reduction strategies based on nutrition, healthy body weight and physical activity. The recommendations from this workshop will be incorporated into a number of CCO's primary prevention initiatives. Risk factor surveillance activities are also being designed to track population trends in the recommended level of physical activity, particularly in relation to new strategies or programs.

The workshop recommendations should be widely disseminated. They will be useful to agencies and organizations concerned with physical activity and fitness, not necessarily in relation to cancer, to further justify their efforts to promote the health benefits of physical activity. They can also be used as part of the strategic justification for funding proposals, program development and policy advocacy efforts of CCO, its partners and other agencies.

Acknowledgements

This workshop was supported by funding from the Prevention Unit, Division of Preventive Oncology, Cancer Care Ontario. We extend our thanks to the 11 scientists who made up the expert panel, whose passion, graciousness and willingness to share in the development of recommendations will assist those working in cancer prevention for the province of Ontario. We would also like to thank the observers for their time, energy and insight and for providing a context for the ongoing implementation of these proceedings.

For further information on the workshop and its recommendations, please contact Dr. Loraine Marrett at Cancer Care Ontario.

References

1. Ontario Task Force on the Primary Prevention of Cancer. Recommendations for the primary prevention of cancer. Toronto: Ontario Ministry of Health, 1995.

2. National Cancer Institute of Canada. Canadian cancer statistics 2000. Toronto: NCIC, 2000.

3. MacNeill I. Projections of mortality and hospital morbidity for leading causes. Report to the Bureau of Operations, Planning and Policy, Laboratory Centre for Disease Control, Health Canada. April 2000.

4. Chief Medical Officer of Health. Progress against cancer. Toronto: Ontario Ministry of Health, 1994.

5. Bailar JC, Gornik H. Cancer undefeated. N Engl J Med 1997;336:1569-74.

6. Miller AB. Canadian contributions to cancer control. Can J Oncology 1994;4:238-42.

7. Harvard Center for Cancer Prevention. Causes of human cancer. Cancer Causes Control 1996;7(Suppl).

8. Parkin DM, Whelan SL, Ferlay J, Raymond L, Young J. Cancer incidence in five continents, Vol VII. IARC Scientific Publications No. 143. Lyon, France: IARC, 1997.

9. Friedenreich CM. Physical activity and cancer: review of the evidence for a preventive role. Report prepared for the Physical Activity and Cancer Prevention Workshop, Cancer Care Ontario; 2000 March 24-25; Toronto, Canada.

10. World Cancer Research Fund/American Institute for Cancer Research. Food, nutrition and the prevention of cancer: A global perspective. Washington DC: American Institute for Cancer Research, 1997.

11. Shephard RJ, Shek PN. Associations between physical activity and susceptibility to cancer: possible mechanisms. Sports Med 1998;26:293-315.

12. McTiernan A, Schwartz RS, Potter J, Bowen D. Exercise clinical trials in cancer prevention research: A call to action. Cancer Epidemiol Biomarkers Prev 1999;8:201-7.

13. Friedenreich CM. Physical activity and cancer prevention: from observational to intervention research. Cancer Epidemiol Biomarkers Prev. In press 2001.

14. Health Canada. Canada's physical activity guide to healthy active living. Ottawa, 1998; Cat. H39-429/1998.

15. Canadian Cancer Society. Seven Steps to Health. <www.cancer.ca/info/pubs/sevene1.htm>. February 2000.

16. Harvard Center for Cancer Prevention. 7 ways to prevent cancer. <www.hsph.harvard.edu/Organizations/Canprevent/7ways.htm>. January 2000.

17. American Cancer Society. Guidelines on diet, nutrition and cancer prevention. May 1999.

18. U.S. Department of Health and Human Services. Healthy People 2000: National health promotion and disease prevention objectives. Washington, DC: U.S. Department of Health and Human Services, Public Health Service, 1990. DHHS Pub No. (PHS) 91-50212.

19. U.S. Department of Health and Human Services. Healthy People 2010. <www.health.gov/healthypeople/Document/HTML/uih/uih_4.htm#physactiv>. January 2000.

20. International Union against Cancer. UICC statement on diet, nutrition and cancer. <www.uicc.org/nutrition/nutristate.shtml>. July 1999.

21. Cancer Care Ontario. An ounce of prevention: Ontario's cancer prevention blueprint 2000. Toronto: Division of Preventive Oncology, Cancer Care Ontario, May 2000. <www.cancercare.on.ca/reports/blueprint/cover.html>.

Author References

Loraine D Marrett, Division of Preventive Oncology, Cancer Care Ontario; and Department of Public Health Sciences, University of Toronto

Beth Theis, Division of Preventive Oncology, Cancer Care Ontario

Frederick D Ashbury, PICEPS Consultants, Inc.; Department of Oncology, McGill University; Faculty of Nursing, University of Manitoba; and Centre for Health Promotion, University of Toronto

Expert panel members listed in Appendix 1

Correspondence: Dr Loraine D Marrett, Division of Preventive Oncology, Cancer Care Ontario, 620 University Avenue, Toronto, Ontario M5G 2L7; Phone: (416) 971-5100, ext. 1214; Fax: (416) 971-6888. Email: Loraine.marrett@cancercare.on.ca

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APPENDIX 1 Participants: Physical Activity and Cancer Prevention Workshop, Cancer Care Ontario, March 24-25, 2000
Expert Panel
Leslie Bernstein Department of Preventive Medicine University of Southern California/Norris Comprehensive Cancer Center Los Angeles, California, USA	Christine Friedenreich* Division of Epidemiology, Prevention and Screening Alberta Cancer Board Calgary, Alberta, Canada	Roy Shephard Faculty of Physical Education and Health University of Toronto Toronto, Ontario, Canada
Carl J Caspersen National Centre for Chronic Disease Prevention and Health Promotion Centers for Disease Control and Prevention Atlanta, Georgia, USA	Marilie D Gammon Department of Epidemiology, School of Public Health University of North Carolina Chapel Hill, North Carolina, USA	Marty Slattery Department of Family and Preventive Medicine University of Utah Salt Lake City, Utah, USA
Kerry Courneya Faculty of Physical Education University of Alberta Edmonton, Alberta, Canada	Charles Matthews Department of Epidemiology and Biostatistics/ South Carolina Cancer Center University of South Carolina Columbia, South Carolina,USA	Inger Thune Department of Epidemiology and Medical Statistics University of Tromsø and Norwegian Cancer Society Tromsø, Norway
Gail McKeown-Eyssen Department of Public Health Sciences University of Toronto Toronto, Ontario, Canada	Anne McTiernan Cancer Prevention Research Program Fred Hutchinson Cancer Research Center Seattle, Washington, USA
Observers
Roy Cameron Centre for Behavioural Research and Program Evaluation University of Waterloo Waterloo, Ontario, Canada	Loraine Marrett* Division of Preventive Oncology Cancer Care Ontario Toronto, Ontario, Canada	Melody Roberts* Division of Preventive Oncology Cancer Care Ontario Toronto, Ontario, Canada
John Garcia Division of Preventive Oncology Cancer Care Ontario Toronto, Ontario, Canada	Paul Ritvo Division of Preventive Oncology Cancer Care Ontario Toronto, Ontario, Canada	Beth Theis* Division of Preventive Oncology Cancer Care Ontario Toronto, Ontario, Canada
Nancy Kreiger* Division of Preventive Oncology Cancer Care Ontario Toronto, Ontario, Canada
Facilitator
	Fred Ashbury* Department of Oncology McGill University Montreal, Quebec, Canada
* Member, Workshop Organizing Committee

APPENDIX 2
Pre-Workshop Questionnaire
Physical Activity and Cancer Prevention Toronto, March 24-25 2000

This survey has been developed to identify workshop participants' perceptions of the state of the evidence (epidemiologic, biologic, intervention research) on physical activity and cancer prevention, and to help identify issues and recommendations. We ask that you draw on your own area of expertise, experience and the materials in this package to complete the questionnaire for submission when you arrive at the workshop. We will summarize your responses and present them during the first morning. We will then return the questionnaire to you and ask that, as the discussion progresses during the day, you revisit your responses periodically.

State of knowledge Please place ticks in the cells that reflect your opinion of the next steps for research or action for each cancer site.

Cancer site
Further research needed

Public health action warranted

Epidemiologic

Biologic mechanisms

Intervention research
(efficacy)*

Intervention research
(effectiveness)*

Public health recommendations

Population intervention programs

Colorectal

Breast

Prostate

Lung

Testicular

Ovarian

Endometrial

Other sites
(please specify)

* Efficacy research is the test of an intervention under ideal conditions (a randomized controlled trial); effectiveness research tests an intervention under routine conditions.

Overall strength of the evidence
1 = strongly agree; 2 = agree; 3 = neutral;
4 = disagree; 5 = strongly disagree

Please circle the number below that best represents your answer

The evidence on the association between physical activity and cancer prevention is sufficiently strong to provide clear direction for public health recommendations and/or interventions.
1 2 3 4 5


	Last Updated: 2002-10-04		Important Notices