Social Class: A stratum of people with similar position and prestige; includes social stratification. Social class is measured by criteria such as education, occupation, and income.Social Behavior: Any behavior caused by or affecting another individual, usually of the same species.Social Support: Support systems that provide assistance and encouragement to individuals with physical or emotional disabilities in order that they may better cope. Informal social support is usually provided by friends, relatives, or peers, while formal assistance is provided by churches, groups, etc.Social Mobility: The movement or shifting of membership between or within social classes by individuals or by groups.Occupations: Crafts, trades, professions, or other means of earning a living.Social Environment: The aggregate of social and cultural institutions, forms, patterns, and processes that influence the life of an individual or community.Social Isolation: The separation of individuals or groups resulting in the lack of or minimizing of social contact and/or communication. This separation may be accomplished by physical separation, by social barriers and by psychological mechanisms. In the latter, there may be interaction but no real communication.WalesSocioeconomic Factors: Social and economic factors that characterize the individual or group within the social structure.EnglandScotlandSocial Perception: The perceiving of attributes, characteristics, and behaviors of one's associates or social groups.Great BritainSocial Adjustment: Adaptation of the person to the social environment. Adjustment may take place by adapting the self to the environment or by changing the environment. (From Campbell, Psychiatric Dictionary, 1996)Social Conditions: The state of society as it exists or in flux. While it usually refers to society as a whole in a specified geographical or political region, it is applicable also to restricted strata of a society.Educational Status: Educational attainment or level of education of individuals.Social Dominance: Social structure of a group as it relates to the relative social rank of dominance status of its members. (APA, Thesaurus of Psychological Index Terms, 8th ed.)Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Social Media: Platforms that provide the ability and tools to create and publish information accessed via the INTERNET. Generally these platforms have three characteristics with content user generated, high degree of interaction between creator and viewer, and easily integrated with other sites.Social Work: The use of community resources, individual case work, or group work to promote the adaptive capacities of individuals in relation to their social and economic environments. It includes social service agencies.Illegitimacy: The state of birth outside of wedlock. It may refer to the offspring or the parents.Hierarchy, Social: Social rank-order established by certain behavioral patterns.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Marriage: The social institution involving legal and/or religious sanction whereby individuals are joined together.Social Sciences: Disciplines concerned with the interrelationships of individuals in a social environment including social organizations and institutions. Includes Sociology and Anthropology.Health Status: The level of health of the individual, group, or population as subjectively assessed by the individual or by more objective measures.Social Justice: An interactive process whereby members of a community are concerned for the equality and rights of all.Employment: The state of being engaged in an activity or service for wages or salary.Fathers: Male parents, human or animal.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Unemployment: The state of not being engaged in a gainful occupation.Smoking: Inhaling and exhaling the smoke of burning TOBACCO.Mortality: All deaths reported in a given population.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Social Change: Social process whereby the values, attitudes, or institutions of society, such as education, family, religion, and industry become modified. It includes both the natural process and action programs initiated by members of the community.Social Distance: The degree of closeness or acceptance an individual or group feels toward another individual or group.Residence Characteristics: Elements of residence that characterize a population. They are applicable in determining need for and utilization of health services.FinlandInfant, Newborn: An infant during the first month after birth.Birth Weight: The mass or quantity of heaviness of an individual at BIRTH. It is expressed by units of pounds or kilograms.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Housing: Living facilities for humans.Histocompatibility Antigens Class I: Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.Social Values: Abstract standards or empirical variables in social life which are believed to be important and/or desirable.Social Problems: Situations affecting a significant number of people, that are believed to be sources of difficulty or threaten the stability of the community, and that require programs of amelioration.Health Surveys: A systematic collection of factual data pertaining to health and disease in a human population within a given geographic area.Histocompatibility Antigens Class II: Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.Social Behavior Disorders: Behaviors which are at variance with the expected social norm and which affect other individuals.Intelligence: The ability to learn and to deal with new situations and to deal effectively with tasks involving abstractions.Life Style: Typical way of life or manner of living characteristic of an individual or group. (From APA, Thesaurus of Psychological Index Terms, 8th ed)Longitudinal Studies: Studies in which variables relating to an individual or group of individuals are assessed over a period of time.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Social Security: Government sponsored social insurance programs.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Psychology, Social: The branch of psychology concerned with the effects of group membership upon the behavior, attitudes, and beliefs of an individual.Body Height: The distance from the sole to the crown of the head with body standing on a flat surface and fully extended.Social Desirability: A personality trait rendering the individual acceptable in social or interpersonal relations. It is related to social acceptance, social approval, popularity, social status, leadership qualities, or any quality making him a socially desirable companion.LondonGermany, WestSocial Identification: The process by which an aspect of self image is developed based on in-group preference or ethnocentrism and a perception of belonging to a social or cultural group. (From APA, Thesaurus of Psychological Index Terms, 8th ed.)Income: Revenues or receipts accruing from business enterprise, labor, or invested capital.Parents: Persons functioning as natural, adoptive, or substitute parents. The heading includes the concept of parenthood as well as preparation for becoming a parent.Poverty: A situation in which the level of living of an individual, family, or group is below the standard of the community. It is often related to a specific income level.Political Systems: The units based on political theory and chosen by countries under which their governmental power is organized and administered to their citizens.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.Social Participation: Involvement in community activities or programs.Social Welfare: Organized institutions which provide services to ameliorate conditions of need or social pathology in the community.Cause of Death: Factors which produce cessation of all vital bodily functions. They can be analyzed from an epidemiologic viewpoint.IrelandSocial Conformity: Behavioral or attitudinal compliance with recognized social patterns or standards.Stress, Psychological: Stress wherein emotional factors predominate.Marital Status: A demographic parameter indicating a person's status with respect to marriage, divorce, widowhood, singleness, etc.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Psychosocial Deprivation: The absence of appropriate stimuli in the physical or social environment which are necessary for the emotional, social, and intellectual development of the individual.Family Characteristics: Size and composition of the family.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Single Parent: A natural, adoptive, or substitute parent of a dependent child, who lives with only one parent. The single parent may live with or visit the child. The concept includes the never-married, as well as the divorced and widowed.Spain: Parliamentary democracy located between France on the northeast and Portugual on the west and bordered by the Atlantic Ocean and the Mediterranean Sea.Alcohol Drinking: Behaviors associated with the ingesting of alcoholic beverages, including social drinking.Social Facilitation: Any enhancement of a motivated behavior in which individuals do the same thing with some degree of mutual stimulation and consequent coordination.Social Alienation: The state of estrangement individuals feel in cultural settings that they view as foreign, unpredictable, or unacceptable.Phobic Disorders: Anxiety disorders in which the essential feature is persistent and irrational fear of a specific object, activity, or situation that the individual feels compelled to avoid. The individual recognizes the fear as excessive or unreasonable.DenmarkPoverty Areas: City, urban, rural, or suburban areas which are characterized by severe economic deprivation and by accompanying physical and social decay.Social Medicine: A branch of medicine concerned with the role of socio-environmental factors in the occurrence, prevention and treatment of disease.Social Marketing: Use of marketing principles also used to sell products to consumers to promote ideas, attitudes and behaviors. Design and use of programs seeking to increase the acceptance of a social idea or practice by target groups, not for the benefit of the marketer, but to benefit the target audience and the general society.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Respiration Disorders: Diseases of the respiratory system in general or unspecified or for a specific respiratory disease not available.Mental Health: The state wherein the person is well adjusted.Health Status Disparities: Variation in rates of disease occurrence and disabilities between population groups defined by socioeconomic characteristics such as age, ethnicity, economic resources, or gender and populations identified geographically or similar measures.Health Behavior: Behaviors expressed by individuals to protect, maintain or promote their health status. For example, proper diet, and appropriate exercise are activities perceived to influence health status. Life style is closely associated with health behavior and factors influencing life style are socioeconomic, educational, and cultural.Ethnic Groups: A group of people with a common cultural heritage that sets them apart from others in a variety of social relationships.Maternal Age: The age of the mother in PREGNANCY.Self Concept: A person's view of himself.Odds Ratio: The ratio of two odds. The exposure-odds ratio for case control data is the ratio of the odds in favor of exposure among cases to the odds in favor of exposure among noncases. The disease-odds ratio for a cohort or cross section is the ratio of the odds in favor of disease among the exposed to the odds in favor of disease among the unexposed. The prevalence-odds ratio refers to an odds ratio derived cross-sectionally from studies of prevalent cases.Parity: The number of offspring a female has borne. It is contrasted with GRAVIDITY, which refers to the number of pregnancies, regardless of outcome.Health Status Indicators: The measurement of the health status for a given population using a variety of indices, including morbidity, mortality, and available health resources.Patient Acceptance of Health Care: The seeking and acceptance by patients of health service.Single Person: The unmarried man or woman.Type A Personality: Established behavior pattern characterized by excessive drive and ambition, impatience, competitiveness, sense of time urgency, and poorly contained aggression.Birth Order: The sequence in which children are born into the family.Child Development: The continuous sequential physiological and psychological maturing of an individual from birth up to but not including ADOLESCENCE.Mothers: Female parents, human or animal.Family: A social group consisting of parents or parent substitutes and children.Adaptation, Psychological: A state of harmony between internal needs and external demands and the processes used in achieving this condition. (From APA Thesaurus of Psychological Index Terms, 8th ed)Attitude to Health: Public attitudes toward health, disease, and the medical care system.Northern IrelandPrejudice: A preconceived judgment made without factual basis.SwedenMorbidity: The proportion of patients with a particular disease during a given year per given unit of population.Sex Distribution: The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Infant Mortality: Postnatal deaths from BIRTH to 365 days after birth in a given population. Postneonatal mortality represents deaths between 28 days and 365 days after birth (as defined by National Center for Health Statistics). Neonatal mortality represents deaths from birth to 27 days after birth.United StatesInfant, Low Birth Weight: An infant having a birth weight of 2500 gm. (5.5 lb.) or less but INFANT, VERY LOW BIRTH WEIGHT is available for infants having a birth weight of 1500 grams (3.3 lb.) or less.Urban Population: The inhabitants of a city or town, including metropolitan areas and suburban areas.Interviews as Topic: Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.Crowding: An excessive number of individuals, human or animal, in relation to available space.Culture: A collective expression for all behavior patterns acquired and socially transmitted through symbols. Culture includes customs, traditions, and language.Family Practice: A medical specialty concerned with the provision of continuing, comprehensive primary health care for the entire family.Education: Acquisition of knowledge as a result of instruction in a formal course of study.Hospitals, State: Hospitals controlled by agencies and departments of the state government.Adoption: Voluntary acceptance of a child of other parents to be as one's own child, usually with legal confirmation.Disabled Persons: Persons with physical or mental disabilities that affect or limit their activities of daily living and that may require special accommodations.Behavior, Animal: The observable response an animal makes to any situation.Age Distribution: The frequency of different ages or age groups in a given population. The distribution may refer to either how many or what proportion of the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Unconscious (Psychology): Those forces and content of the mind which are not ordinarily available to conscious awareness or to immediate recall.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.House Calls: Visits to the patient's home by professional personnel for the purpose of diagnosis and/or treatment.Urban Health: The status of health in urban populations.West Indies: Islands lying between southeastern North America and northern South America, enclosing the Caribbean Sea. They comprise the Greater Antilles (CUBA; DOMINICAN REPUBLIC; HAITI; JAMAICA; and PUERTO RICO), the Lesser Antilles (ANTIGUA AND BARBUDA and the other Leeward Islands, BARBADOS; MARTINIQUE and the other Windward Islands, NETHERLANDS ANTILLES; VIRGIN ISLANDS OF THE UNITED STATES, BRITISH VIRGINI ISLANDS, and the islands north of Venezuela which include TRINIDAD AND TOBAGO), and the BAHAMAS. (From Webster's New Geographical Dictionary, 1988, p1330)Coronary Disease: An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.Cognition: Intellectual or mental process whereby an organism obtains knowledge.Mental Disorders: Psychiatric illness or diseases manifested by breakdowns in the adaptational process expressed primarily as abnormalities of thought, feeling, and behavior producing either distress or impairment of function.Quality of Life: A generic concept reflecting concern with the modification and enhancement of life attributes, e.g., physical, political, moral and social environment; the overall condition of a human life.Ownership: The legal relation between an entity (individual, group, corporation, or-profit, secular, government) and an object. The object may be corporeal, such as equipment, or completely a creature of law, such as a patent; it may be movable, such as an animal, or immovable, such as a building.Emigration and Immigration: The process of leaving one's country to establish residence in a foreign country.Demography: Statistical interpretation and description of a population with reference to distribution, composition, or structure.Neoplasms: New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.Dominance-Subordination: Relationship between individuals when one individual threatens or becomes aggressive and the other individual remains passive or attempts to escape.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Body Mass Index: An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)Cardiovascular Diseases: Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Rural Population: The inhabitants of rural areas or of small towns classified as rural.Epidemiologic Methods: Research techniques that focus on study designs and data gathering methods in human and animal populations.Health Services Accessibility: The degree to which individuals are inhibited or facilitated in their ability to gain entry to and to receive care and services from the health care system. Factors influencing this ability include geographic, architectural, transportational, and financial considerations, among others.Paternal Exposure: Exposure of the male parent, human or animal, to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals that may affect offspring.Rural Health: The status of health in rural populations.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Social Responsibility: The obligations and accountability assumed in carrying out actions or ideas on behalf of others.Twins: Two individuals derived from two FETUSES that were fertilized at or about the same time, developed in the UTERUS simultaneously, and born to the same mother. Twins are either monozygotic (TWINS, MONOZYGOTIC) or dizygotic (TWINS, DIZYGOTIC).Peer Group: Group composed of associates of same species, approximately the same age, and usually of similar rank or social status.Social Determinants of Health: The circumstances in which people are born, grow up, live, work, and age, as well as the systems put in place to deal with illness. These circumstances are in turn shaped by a wider set of forces: economics, social policies, and politics (http://www.cdc.gov/socialdeterminants/).Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Confounding Factors (Epidemiology): Factors that can cause or prevent the outcome of interest, are not intermediate variables, and are not associated with the factor(s) under investigation. They give rise to situations in which the effects of two processes are not separated, or the contribution of causal factors cannot be separated, or the measure of the effect of exposure or risk is distorted because of its association with other factors influencing the outcome of the study.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Obesity: A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).Social Stigma: A perceived attribute that is deeply discrediting and is considered to be a violation of social norms.African Americans: Persons living in the United States having origins in any of the black groups of Africa.Breast Feeding: The nursing of an infant at the breast.Depression: Depressive states usually of moderate intensity in contrast with major depression present in neurotic and psychotic disorders.Self-Assessment: Appraisal of one's own personal qualities or traits.Diet: Regular course of eating and drinking adopted by a person or animal.Censuses: Enumerations of populations usually recording identities of all persons in every place of residence with age or date of birth, sex, occupation, national origin, language, marital status, income, relation to head of household, information on the dwelling place, education, literacy, health-related data (e.g., permanent disability), etc. The census or "numbering of the people" is mentioned several times in the Old Testament. Among the Romans, censuses were intimately connected with the enumeration of troops before and after battle and probably a military necessity. (From Last, A Dictionary of Epidemiology, 3d ed; Garrison, An Introduction to the History of Medicine, 4th ed, p66, p119)Friends: Persons whom one knows, likes, and trusts.Health Knowledge, Attitudes, Practice: Knowledge, attitudes, and associated behaviors which pertain to health-related topics such as PATHOLOGIC PROCESSES or diseases, their prevention, and treatment. This term refers to non-health workers and health workers (HEALTH PERSONNEL).Environment: The external elements and conditions which surround, influence, and affect the life and development of an organism or population.Schools: Educational institutions.Poisoning: A condition or physical state produced by the ingestion, injection, inhalation of or exposure to a deleterious agent.Intelligence Tests: Standardized tests that measure the present general ability or aptitude for intellectual performance.Proportional Hazards Models: Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.Social Work, Psychiatric: Use of all social work processes in the treatment of patients in a psychiatric or mental health setting.Sociology: A social science dealing with group relationships, patterns of collective behavior, and social organization.History, 20th Century: Time period from 1901 through 2000 of the common era.Linear Models: Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.Emotions: Those affective states which can be experienced and have arousing and motivational properties.BrazilReinforcement, Social: The strengthening of a response with a social reward such as a nod of approval, a parent's love or attention.Personality: Behavior-response patterns that characterize the individual.Eczema: A pruritic papulovesicular dermatitis occurring as a reaction to many endogenous and exogenous agents (Dorland, 27th ed).Bias (Epidemiology): Any deviation of results or inferences from the truth, or processes leading to such deviation. Bias can result from several sources: one-sided or systematic variations in measurement from the true value (systematic error); flaws in study design; deviation of inferences, interpretations, or analyses based on flawed data or data collection; etc. There is no sense of prejudice or subjectivity implied in the assessment of bias under these conditions.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Social Planning: Interactional process combining investigation, discussion, and agreement by a number of people in the preparation and carrying out of a program to ameliorate conditions of need or social pathology in the community. It usually involves the action of a formal political, legal, or recognized voluntary body.Registries: The systems and processes involved in the establishment, support, management, and operation of registers, e.g., disease registers.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.Adolescent Behavior: Any observable response or action of an adolescent.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.European Continental Ancestry Group: Individuals whose ancestral origins are in the continent of Europe.Occupational Diseases: Diseases caused by factors involved in one's employment.Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Continental Population Groups: Groups of individuals whose putative ancestry is from native continental populations based on similarities in physical appearance.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.ItalySchizophrenia: A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.Suicide: The act of killing oneself.Body Constitution: The physical characteristics of the body, including the mode of performance of functions, the activity of metabolic processes, the manner and degree of reactions to stimuli, and power of resistance to the attack of pathogenic organisms.Exercise: Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.