The Epidemiology of Obesity

Obesity Trend in Adults and Children

Surveillance Systems
Prevalence was the highest among Black women Beta coefficients were used to indicate the average annual increases in prevalence. Critical points should be addressed when planning an injury surveillance system in a developing country. Social environmental factors might have a more profound effect in influencing individuals' body weight status than do individuals' characteristics such as SES. Persons using assistive technology might not be able to fully access information in this file.

Definitions and Basic Concepts

Guidelines for Evaluating Surveillance Systems

In the late s, the Philippine Department of Health PDOH , relying on its integrated management information system, detected less than one outbreak per year in a population of more than 60 million people. In , the PDOH designed the National Epidemic Sentinel Surveillance System, a hospital-based sentinel surveillance system that encompasses both the flow of data and the personnel requirements needed to make the surveillance system work effectively table After the pilot study demonstrated promising results, the PDOH created personnel positions and a supervisory structure for sentinel physicians, nurses, and clerks in regional epidemiology and surveillance units RESUs integrated into the public health system.

In alone, the system detected and formally investigated about 80 outbreaks, including 25 bacteriologically confirmed outbreaks of typhoid and 5 of cholera.

By integrating surveillance functions that were based on the skills of the workforce, PDOH was able to avoid the duplications, inefficiencies, and sustainability problems of multiple vertical systems White and McDonnell WHO and other agencies frequently receive telephone calls or informal reports about urgent health events. WHO publishes an informal list of these"rumors,"which allows public health workers to respond to health risks promptly rather than waiting for formal reports http: FETPs and allied programs both train epidemiologists and provide service to their ministries of health.

For example, a student in the Brazilian FETP was assigned to review routine data on patients with leishmaniasis. She noted that some patients had symptoms of heavy metal poisoning, and further study indicated that a drug being used to treat leishmaniasis was contaminated with heavy metals.

The drug was reformulated, and the problem was resolved. Large categorical surveillance systems are expensive, and staff members might become complacent, especially if the disease under surveillance is rare. For example, the polio surveillance system for acute flaccid paralysis in the Western Hemisphere detected no cases in July A trainee from the FETP of the Dominican Republic, while investigating a case of suspected poisoning in a child, documented the first outbreak of circulating vaccine-type poliovirus in the Western Hemisphere since There were 13 confirmed cases in the Dominican Republic and 8 cases in Haiti.

Her investigation led to national immunization days in both countries, which raised immunization levels and stopped the outbreak Kew and others It seems incredible that a disease as devastating as AIDS could have spread silently to many countries over many years before it was detected and before effective control measures were implemented in the s. In recent years, surveillance and response systems at all levels have been more effective at identifying and preventing spread of infectious diseases.

An epidemic of severe pneumonia of unknown etiology was detected in Guangdong province, China, in November , and control measures were instituted on the basis of the way the disease spread from person to person. This new disease was named severe acute respiratory syndrome , and a preliminary case definition was established on the basis of initial epidemiologic investigations.

This global pandemic ended in July , as transmission was interrupted in Taiwan China , after more than 8, patients in 26 countries and five continents were affected and deaths were confirmed Peiris and others WHO spearheaded the global effort to control this pandemic, working with national and subnational health workers. They instituted surveillance, conducted epidemiologic investigations, designed prevention and control guidelines, responded to inquiries from the media and the public, and planned and implemented epidemiologic studies http: The success of this global effort to control the first new epidemic disease of the 21st century depended on a combination of open collaboration among scientists and politicians of many countries and the rapid and accurate communication of surveillance data within and among countries.

Rapid global spread was recognized, and a global surveillance network was established on the basis of an agreed-upon case definition that was sufficiently specific to ensure effective reporting.

Public health surveillance is critical to recognizing new cases of SARS and differentiating this disease from other causes of severe respiratory illness, especially influenza Heymann and Rodier Ongoing research into sources in the environment as well as clinical, laboratory, and epidemiologic concerns will improve surveillance for this critical public health problem.

Notably, this highly contagious disease—for which there is neither a vaccine nor a cure—was controlled by competent, dedicated health workers with access to excellent communications. SARS presented a greater challenge than smallpox, for which long incubation periods and vaccine facilitate control Mack Although it is reassuring that national, regional, and global systems were effective in controlling SARS, there is no reason to rest on our laurels.

The only certainty is that there will be more new challenges, very possibly including further outbreaks of SARS. The disastrous pandemic worldwide epidemic of influenza in is thought to have originated from epidemics in birds, as were the influenza pandemics of and Ungchusak and others In early , large epidemics of avian influenza were recognized in birds in eight Asian countries; by November, the disease had spread from birds to 44 humans, 73 percent of whom died Ungchusak and others This contagion sparked fears that the highly lethal avian virus might be adapting to spread from person to person, which could cause extensive health and economic damage around the world.

By applying field epidemiologic techniques supported by laboratory studies, they detected that the virus was being spread from human to human in a family.

It is likely that person-to-person transmission may have occurred in other countries, where field epidemiology was not used. The Thai example is important for achieving the following: He found a hospital jammed with patients with high fevers, diarrhea, and bleeding. He diagnosed viral hemorrhagic fever. She agreed with his diagnosis and arranged for samples to be rushed to the National Institute for Virology in South Africa, the nearest WHO reference center for viral hemorrhagic fevers.

When the minister of health arrived at his office the next day, the graduate briefed him. Recognizing the gravity of the situation, the minister sent the graduate to head the public health team surveillance and control team in Gulu, and the student headed the clinical team that established infection control in hospitals and treated patients.

Laboratory tests quickly confirmed that the illness was Ebola hemorrhagic fever, which usually kills more than 50 percent of those infected Heymann Public health surveillance was difficult for several reasons. Because the disease was severe and rapidly fatal, rural villagers feared that they might be stigmatized if the government knew about cases in their area.

Some sought out traditional healers; others fled as soon as they realized they had been exposed, which prompted outbreaks in two other districts. Gulu was a politically unstable area, and some villages were difficult to reach because of rebel or bandit activity. Patients with Ebola infection require intense nursing and medical attention to control bleeding, diarrhea, and fevers. Some patients bleed easily, and all their secretions can be highly infectious. Hospitals in Gulu were desperately short of supplies to control the spread of infection from so many patients simultaneously.

In spite of this situation, Ugandan health workers selflessly cared for the sick. By January 23, , a total of cases had occurred, the largest Ebola outbreak recorded. Only 53 percent of the patients had died, a proportion far less than the 88 percent reported in the Ebola outbreak in the Democratic Republic of Congo formerly Zaire and other previous epidemics WHO Report of an International Commission Sadly, 22 health care workers were infected.

Because the team from the Ugandan Ministry of Health set up active surveillance nationwide, the other two outbreaks, started when infected Gulu residents fled to distant villages, were quickly detected and controlled. International observers commented, "National notification and surveillance efforts led to the rapid identification of these foci and to effective containment" CDC Both students and graduates contributed to the ministry's ability to rapidly identify and control this dangerous epidemic.

Because the minister had timely evidence, he was able to notify other countries quickly and to bring in international teams before the disease spread further.

Partially because of the lessons learned from this epidemic, Uganda has become one of the leading countries in implementing the IDSR program. Surveillance systems are important tools for targeting, monitoring, and evaluating many health risks and interventions. Because managers need a wide variety of information for specific interventions, systems have been developed and tested to meet those needs.

Surveillance for environmental public health practice requires the collection, analysis, and dissemination of data on hazards, exposures, and health outcomes figure Health outcomes of relevance include death, disease, injury, and disability.

However, relating those outcomes to specific environmental hazards and exposures is critical to environmental public health surveillance. Hazards include toxic chemical agents, physical agents, biomechanical stressors, and biologic agents that are located in air, water, soil, food, and other environmental media. Exposure surveillance is the monitoring of members of the population for the presence of an environmental agent, its metabolites, or its clinically inapparent for example, subclinical or preclinical effects.

Four challenges complicate environmental public health surveillance. First, the ability to link specific environmental causes to adverse outcomes is limited by our poor understanding of disease processes, long lead times, inadequate measures of exposure, and multiple potential causes of disease.

Second, data collected for other purposes rarely include sufficient information to meet a case definition for a condition caused by an environmental agent. Third, public alarm is often out of proportion to the hazard of concern, and sentiment will often influence public policy disproportionately to scientific information. Fourth, biologic markers will become increasingly critical elements of environmental exposure surveillance.

Obtaining data on exposure, which can include estimates derived from hazard data through sophisticated modeling or direct measurements of individual exposure obtained from use of personal monitors for example, passive air samplers , is generally impractical in developing countries. Childhood blood lead levels are the only biomonitoring data that are collected routinely in several countries, either in national surveys or from screening programs for children at high risk.

Health outcome surveillance as applied to environmental public health is similar to traditional surveillance efforts. In the United States, the focus is on surveillance for birth defects; developmental disabilities for example, cerebral palsy, autism, and mental retardation ; asthma and other chronic respiratory diseases for example, bronchitis and emphysema ; cancer; and neurological diseases for example, Parkinson's disease, multiple sclerosis, and Alzheimer's disease McGeehin, Qualters, and Niskar Other nations have different sets of priority conditions for surveillance.

Disease registries, vital statistics data, annual health surveys, and administrative data systems for example, hospital discharge data are sources that have been used for monitoring health conditions. The challenges mentioned previously have constrained our ability in all nations, regardless of level of development, to establish and maintain effective and comprehensive environmental public health surveillance systems. As we invest in understanding the enlarging threats in the global environment, we must overcome these challenges and establish improved surveillance systems.

The health of the global community depends on this investment. Injuries are a major public health problem and are among the 10 leading causes of death worldwide, killing an estimated 5 million persons each year and causing high rates of disability. People from all economic groups are at risk for injuries, but death rates caused by injury tend to be higher in developing countries Peden, McGee, and Sharma Injury surveillance includes monitoring the incidence, causes, and circumstances of fatal and nonfatal injuries.

Injuries are classified by the intention of the act into two groups: If the range of fatal and nonfatal injuries, as well as the risk factors that can lead to injury, are to be fully captured, surveillance systems need to be established in multiple settings. Fatal injuries can be captured by using forensic or death certificate data.

A far greater number of injuries are nonfatal and can be tracked through hospital- or primary care—based systems. Systematic information on nonfatal injuries, including prevalence, incidence, and related risk behaviors can also be obtained through ongoing population-based surveys. Critical points should be addressed when planning an injury surveillance system in a developing country.

First, data sources need to be clarified. In some developing countries, routine data on injuries are not always captured in health information systems. It is therefore necessary to consider other sources of data—for example, law enforcement agencies, coroners, or medical examiners. Next, the events and variables in an injury surveillance system should be defined according to the objectives of the system.

Criteria such as the intentionality violence-related injuries versus unintentional injuries ; the outcome fatal injuries versus nonfatal injuries ; and the nature of violence-related injuries physical, sexual, psychological, deprivation, or neglect should be considered when establishing the system. Finally, case definitions and coding procedures should be defined before implementing the system. Under the system, a reportable case is defined as a patient who died from or was treated for an injury in the ED.

Cases include patients with unintentional and violence-related injuries. ED staff members identify cases and collect data in five hospitals in Nicaragua. Information used to complete the instrument is collected directly from the patients or their representatives.

An ED admission clerk collects basic demographic data on the patient's arrival. ED medical staff members physicians and nurses collect the remaining information for example, location, mechanism of injury, nature, severity, and circumstances surrounding the injury during triage and assessment. The hospital epidemiologist collects data collection forms daily from the ED, reviews the quality of data, and requests data from the ED staff if the forms are incomplete.

The statistician reviews data daily. The country project coordinator also monitors the quality of the data periodically. Using Epi Info programs developed specifically for this project, the project coordinators analyze trends and identify potential risk factors Noe and others The information is used to produce monthly reports for dissemination. Information is reported at both the regional and the country levels. Injury prevention programs in Nicaragua use surveillance data to assess the need for new policies or programs and to evaluate the effectiveness of existing policies and programs.

For example, the municipality of León is using the information from the hospital to monitor the increase in suicide attempts among youths abusing pesticides and to evaluate an intersectoral campaign to promote life that includes primary through tertiary prevention strategies.

Surveillance for biologic terrorism is conducted primarily for outbreak detection and management. Surveillance must support early detection of an incident of biologic terrorism and its characterization in the same manner as for the detection and control of naturally occurring outbreaks of infectious diseases. Early detection of outbreaks can be achieved by the following Buehler and others Environmental detection systems for microbial pathogens and toxins of concern for biologic terrorism might also be categorized as new types of data early in the course of an outbreak, before infection Meehan and others The primary surveillance tools for event detection and management are the traditional disease-reporting systems for notifiable diseases discussed elsewhere in this chapter.

These core surveillance tools should be robust before new data types can be considered for supplementing public health surveillance. Syndromic surveillance is an investigational approach by which health department staff members, assisted by automated data acquisition and generation of statistical signals computerized algorithms , monitor disease indicators continually to detect outbreaks of disease earlier and more completely than might otherwise be possible with traditional reportable disease methods Buehler and others CDC's list of biologic terrorism agents and diseases can be found at http: The key elements in planning a disaster surveillance system are establishing objectives, developing case definitions, determining data sources, developing simple data collection instruments, field testing the methods, developing and testing the analysis strategy, developing a dissemination plan for the report or results, and assessing the usefulness of the system.

The surveillance needs are different in the preimpact, impact, and postimpact phases Binder and Sanderson The role of surveillance in disaster situations has included the following broad framework of activities:. Support of relief efforts following national and global disasters has been a relatively new application of epidemiologic practice for the public health professionals.

Nevertheless, since the initial CDC involvement with the United Nations in a large-scale relief effort concerning approximately 20 million displaced people affected by the —70 civil war in Nigeria, CDC staff members have participated in several assessments of the health needs, damage, and nutrition in refugee populations resulting from man-made and natural disasters.

The more notable and extended actions were conducted in the —82 Khmer Thailand-Cambodia refugee-relief action, followed by long-term public health surveillance of Somalian refugees —83 , periodic but comprehensive health and nutritional assessments of Afghan refugees in Pakistan — , and growth and nutritional assessments of internally displaced populations—especially children—in the Democratic People's Republic of Korea s and southern Sudan.

Although these relief efforts occurred many years and many thousands of miles apart, they shared several important characteristics:. The major goal of these activities is to identify and eliminate preventable causes of morbidity and mortality. Planning requires effective use of existing knowledge about characteristic or predictable demographic patterns, easily applied health indicators, and avoidable errors of omission or commission. As in disasters, the principles of surveillance data collection, data analysis, response to data, and assessment of response and other public health techniques should be an integral part of relief efforts.

Retrospective evaluation of these efforts has also proved useful CDC Development and evaluation of policies for health improvement require a reliable assessment of the burden of disease and injury, an inventory of the disposition of resources for health, assessment of the policy environment, and information on the cost effectiveness of interventions and strategies.

In all these areas, consideration of noncommunicable mostly chronic conditions becomes critical. In , noncommunicable diseases were estimated to cause approximately 60 percent of the deaths in the world and 43 percent of the global burden of disease WHO a.

WHO forecasts that by the burden of disease from noncommunicable diseases for developing and newly industrialized countries will have increased more than 60 percent Murray and Lopez Some developing countries have found it difficult to acquire and analyze accurate mortality statistics regularly, let alone morbidity and quality-of-life information. Ensuring development, implementation, and widespread use of noncommunicable disease data for better decisions on resource allocation is critical to improving the quality of lives and promoting a more equitable future for health within and between countries.

Hypertension , elevated blood cholesterol, tobacco use, excessive alcohol consumption, obesity, and the multiple diseases linked to these risk factors are a global public health problem. In one study, smoking, high blood pressure, and high cholesterol alone explained approximately two-thirds to three-fourths of heart attacks and strokes Vartiainen and others Until recently, surveillance for risk factors was an activity commonly associated with developed countries Holtzman However, recently WHO has increased attention to noncommunicable disease surveillance by developing tools and working to achieve data comparability between countries WHO c.

Data on key health behaviors, obesity, hypertension, lipids, and diabetes are collected inconsistently in developing countries, especially in Africa. Data on tobacco use are available through the Global Youth Tobacco Survey http: Incidence data the number and proportion of new cases in a population are limited in developing countries. However, India's National Cancer Registry program may serve as a notable exception http: In , the Indian Council of Medical Research, recognizing that there was a lack of information on follow-up of cancer patients to assess quality of care, instituted a cancer registry network.

The network provides data on the magnitude and patterns of cancer in eight areas of India to enable studies of the histologic features correlating with prognosis and association studies for example, whether a history of vasectomy is associated with cancer of the prostate.

Another important example relates to the widespread use of folic acid in China and the resultant reduction in incidence of birth defects Kelly and others ; Wald Surveillance data have been critical in establishing the importance of obesity as a public health priority in the United States. These data provide a measure of the effectiveness of interventions to meet the control objectives. The BRFSS is a practical tool for developing and middle-income countries, as Jordan demonstrated when it implemented a BRFSS in ; the first survey documented substantial levels of obesity, especially among women, combined with low levels of physical activity CDC b.

Public health surveillance is considered a global public good Zacher , particularly when it is used for eradication of such diseases as poliomyelitis.

As eradication campaigns decrease the number of cases, maintaining systems to find the last few cases becomes more expensive. Often, the majority of the costs for these systems fall on hard-pressed developing countries.

This factor raises questions of fairness and equity. For example, as poliomyelitis becomes rare, it ceases to be a significant risk to national populations, whereas other diseases, such as malaria and diarrhea, typically are major causes of morbidity and mortality. In such countries, it seems most fair and efficient for the global community to finance eradication campaigns, leaving national systems free to address the diseases that most affect their populations.

The negative impact of globally mandated eradication surveillance systems can be mediated or reversed by leveraging on the eradication program's infrastructure to gather surveillance data for diseases of concern to local governments Nsubuga, McDonnell, and others A similar case can be made for influenza early warning systems in countries that gather information that will be used to create vaccines that will benefit other populations but not their own.

Overweight Trends in U. Global Trends of Obesity The current epidemic of obesity has been reported in several but not all regions globally. Possible Causes of the Obesity Epidemic Obesity is caused by a complex interaction between the environment, genetic predisposition, and human behavior.

Burden of Illness Associated with Obesity Obesity is associated with an increased risk of death. Summary and Conclusions The prevalence of obesity in the U. Population-based prevention of obesity: US Centers for Disease control and Prevention.

Prevalence and trends in overweight among US children and adolescents, — Prevalence and trends in obesity among US adults, — Obesity among adults in the United States— no change since — The epidemiology of obesity.

High body mass index for age among US children and adolescents, — The emerging epidemic of obesity in developing countries. Nishida C, Mucavele P. Monitoring the rapidly emerging public health problem of overweight and obesity: Secular trends in patterns of self-reported food consumption of adult Americans: Am J Clin Nutr.

Do we fatten our children at the television set? Obesity and television viewing in children and adolescents. Obesity and the community food environment: Food and park environments: Andreasen CH, Andersen G. Gene-environment interactions and obesity-further aspects of genomewide association studies. Heterogeneity of linkage disequilibrium in human genes has implications for association studies of common diseases.

A common variant in the FTO gene is associated with body mass index and predisposes to childhood and adult obesity. Obesity Silver Spring April; 16 4: Impact of variation in the FTO gene on whole body fat distribution, ectopic fat, and weight loss. Obesity Silver Spring August; 16 8: Low physical activity accentuates the effect of the FTO rs polymorphism on body fat accumulation.

The spread of obesity in a large social network over 32 years. Related Topics Diabetes Nutrition. Recommend on Facebook Tweet Share Compartir. Youth Risk Behavior Surveillance System YRBS YRBSS measures the prevalence obesity and monitors six types of health-risk behaviors that contribute to the leading causes of death and disability among youth and young adults, including unhealthy dietary behaviors and physical inactivity.

NHIS data are collected through personal household interviews. This includes nutrition services, education, and policies. School Health Profiles Profiles The School Health Profiles is a system of surveys assessing school health policies and practices in states, large urban school districts, territories, and tribal governments. This includes school health education requirements, nutrition and dietary behavior topics and school health policies and practices related to nutrition and other topics.

Physical Activity Explanation of US Physical Activity Surveys Several different national surveys track physical activity in many age groups and at several levels for the United States national public health objectives.

Types of surveillance