Presentation on theme: "Nutrition and Health surveys/nutrition monitoring; Epidemiology"— Presentation transcript:
1Nutrition and Health surveys/nutrition monitoring; Epidemiology Chapters 5 & 7
2Practice of Epidemiology Initially used to investigate, control, and prevent epidemics of infectious diseaseEpidemiologists work with other health professionalsto identify causes of diseaseto propose strategies for controlling or preventing health problemsCan be used to describe a community’s health problems and to determine whether health is improving or getting worseSurveillance methods have been used to monitor preventable causes of birth defects
3Epidemiology“the study of the __________ and ___________ of health-related states and events in specified populations and the application of this study to control of health problems”
4Study—Epidemiology is the basic science of public health Study—Epidemiology is the basic science of public health. It's a highly quantitative discipline based on principles of statistics and research methodologies.Distribution—Epidemiologists study the distribution of frequencies and patterns of health events within groups in a population. To do this, they use descriptive epidemiology, which characterizes health events in terms of time, place, and person.Determinants—Epidemiologists also attempt to search for causes or factors that are associated with increased risk or probability of disease. This type of epidemiology, where we move from questions of "who," "what," "where," and "when" and start trying to answer "how" and "why," is referred to as analytical epidemiology.Health-related states—Although infectious diseases were clearly the focus of much of the early epidemiological work, this is no longer true. Epidemiology as it is practiced today is applied to the whole spectrum of health-related events, which includes chronic disease, environmental problems, behavioral problems, and injuries in addition to infectious disease.Populations—One of the most important distinguishing characteristics of epidemiology is that it deals with groups of people rather than with individual patients.Control—Finally, although epidemiology can be used simply as an analytical tool for studying diseases and their determinants, it serves a more active role. Epidemiological data steers public health decision making and aids in developing and evaluating interventions to control and prevent health problems. This is the primary function of applied, or field, epidemiology.
5Basic ConceptsRisk“likelihood that people who are without a disease, but exposed to certain risk factors, will acquire the disease at some point in their lives”Risk factors may be found in the physical environment or social environment, or they may be inherited.Other risk factors may be behavioral, such as smoking.
6Relative risk“Measure of how much a particular risk factor influences the risk of a specified outcome”- to identify differences in disease rates between exposed and unexposed groupsRelative Risk = Rate of condition among exposed divided by rate of condition among unexposed
7Incidence“the proportion of group initially free of a disease that develops the disease over a period of time”
8Prevalence“the proportion of a group possessing a disease at a specific time”
10Epidemiological Method Hypothesis testingIdentify a cause-effect comparison to be testedExplaining research observationsBiasChanceTruth
11Types of Epidemiologic Studies Ecological or Correlational StudiesCompare the frequency of events in different populations with the per capita consumption of certain dietary factors.Dietary data collected in this type of study are usually disappearance data, which are the figures for food produced for human consumption minus the food that is exported, fed to animals, wasted, or otherwise not available for human consumption.Cross-sectional or Prevalence StudiesExamine the relationships among dietary intake, diseases, and other variables as they exist in populations at a particular time.
12Types of Epidemiologic Studies Cohort StudiesA group of people, called a cohort, free from the disease is identified and examined, and then followed for months or even yearsGroup members are examined periodically to determine which individuals develop the characteristics of interest and which do not.- _____________ - look back in time to reconstruct exposures and health outcomes, or- _____________ - those that follow a group into the future.
13Types of Epidemiologic Studies Case-Control StudiesA group of persons with the disease is compared with a group of persons without the disease to compare characteristics, such as previous exposure to a factor, between cases and controls.Controlled TrialsThe most rigorous evaluation of a dietary hypothesis is the randomized controlled trial conducted as a double-blind experiment.
14Nutritional epidemiology The epidemiologic method lends itself to the study of the relationship of diet to health and disease.The method can also be used to:Describe the nutrition status of populations or specific subgroups of a populationdevelop specific programs or services for members of the group whose nutrition status appears to be compromised.Evaluate nutrition interventions.
15National nutrition policy - a set of nationwide guidelines that specify how the nutritional needs of the population will be met.- there is no one federal body or agency with its sole mandate to establish, implement, and evaluate national nutrition policy.U.S. national nutrition policyFood assistance programs.National nutrition and health objectives.Regulations to safeguard the food supply and ensure safe handling of food.Dietary guidance systems.Monitoring and surveillance programs.Food labeling legislation.
16National Nutrition Policy Does the U.S. have a national nutrition policy?
17Why monitor nations health and nutritional status? Nations monitor health and nutrition status- to decide how to allocate scarce resources,- to enhance the quality of life,- to improve productivity.Nutrition monitoring is a term that includes:Nutrition assessmentNutrition monitoringNutrition surveillanceNutrition screening
18Background on Nutrition Monitoring in the United States The U.S. government has been involved in tracking certain elements of the food supply and food consumption for more than 8 decades.The first USDA Household Food Consumption SurveyThe nation’s first comprehensive survey (Ten-State Nutrition Survey) conducted between 1968 and 1970.In 1990 Congress passed legislation that established the National Nutrition Monitoring and Related Research Program (NNMRRP).It includes more than 50 surveillance activities that monitor and evaluate the health and nutritional status of the U.S. population.
19Types of data__________ data: relate directly to the population served; often collected by the acting agency itselffocus groups, local surveys__________ data: relate to already existing data in either published or unpublished formNNMRR data
20National Nutrition Monitoring System NNMRRP = National Nutrition Monitoring and Related Research Program
21National Nutrition Monitoring and Related Research Program (NNMRRP) Established by Congress in 1990Implementation and coordination of activities by USDA and DHHSMonitoring data are used to assess the dietary, nutritional, and related health status of the populationMore than 50 surveillance systems are operative
22NNMRRP Goals Collect, analyze, and disseminate data… Establish _________ data and uniform standardsProvide data to evaluate proposed ______ changes
23NNMRRP GoalsProvide scientific foundation for improving nutritional status and quality of food supplyIdentify high risk groups to aid program planning
24National Nutrition Monitoring System Federally mandated collection and analysis of data on:national food supplyfood compositionfood and nutrient consumptionconsumer knowledge, attitudes, behaviorsnutritional/health status
25National Food Supply U.S. Food Supply Series Quantities available per capita of:foodkcals availablenutrientsUSDA
26Food Composition USDA Nutrient Data Base Used for: survey analysis researchindividual use
27Food & Nutrient Consumption Ten State SurveyNationwide Food Consumption Survey (NFCS)Continuing Survey of Food Intakes by Individuals (CSFII)USDA Fruits & Veggies — More Matters(5 A Day for Better Health)NCI…
28Food and Nutrient Consumption “What We Eat in America Survey”Dietary interview component of NHANESIndividuals in households, one sample with all levels of income, another of low-income householdsOne-day and 3-day food intakes of individuals (1-day recall, 2-day record)Times of eating occasionsSources of food eaten away from home
29Food and Nutrient Consumption Total Diet Study (TDS)Eight age groups, infant through elderlyAssesses for nutrients and contaminants in foodsEstimates levels of 11 essential mineralsCollects and analyzes 234 foods from retail markets in urban areas
30KAB Assessments Behavioral Risk Factor Surveillance System (BRFSS) annually since 1984designed to examine trends over time.States can readily address urgent and emerging health issues.BRFSS questions focus on:Not getting enough physical activityEating a high-fat, low-fiber dietUsing tobacco and alcoholNot getting medical care that is known to save lives- e.g. mammograms, Pap smears, colorectal cancer screening, and flu shots- Food frequencies for dietary fat, fruit, and vegetable consumptionYouth Risk Behavior Survey (YRBS)Diet and Health Knowledge Survey (DHKS)
31Nutrition and Health Status National Health and Nutrition Examination Surveys (NHANES I, II, III)“What we eat in America” (integration of NHANES & CSFII)Hispanic Health and Nutrition Examination Survey (HHANES)DHHSPediatric Nutrition Surveillance System (PedNSS)CDC
32Nutritional Status and Nutrition-Related Health Measurements National Health and Nutrition Examination Survey (NHANES) SeriesRepresentative sample of civilian noninstitutionalized population ages 2 months and olderDietary intake (one 24-hour recall)Body compositionBiochemical analyses of blood and urineBone densityDietary and health behaviorsCollects data at household, family, and individual level
33Food Composition and Nutrient Data Base National Nutrient Data Bank (established in 1892) – updated on a regular basisNutrient content of foodsPublished tables of food compositionComputerized databases
34Food Composition and Nutrient Data Base USDA Nutrient Data Base for Standard Reference (initiated in 1980) – produced from National Nutrient Data BankIncludes data on food energy, 28 food components, and 18 amino acids for about 5,200 food itemsMain source of data for USDA Survey Nutrient Data Base
35Food Composition and Nutrient Data Base USDA Survey Nutrient Data Base - updated continuouslyUsed for analysis of nationwide dietary intake surveysIncludes data on food energy and 28 food components for >7,100 food items
36Uses of NMRR Data Assessment of dietary intake Monitoring and Surveillance_________Food programs and GuidanceScientific ResearchHistorical ______