A description of difficult words.
Absolute risk: The probability of an event in the population under study. Defined as the number of events in a group divided by the total number of subjects in that group.
Additional/excess risk: The difference between the proportion of subjects in a population with a particular disease who were exposed to a specified risk factor and the proportion of subjects with that same disease who were not exposed.
All-cause mortality: An estimate of the number of persons in a population who died from any cause in a specified period.
Antioxidant: Any of various substances that inhibit oxidation or reactions promoted by oxygen and peroxides and include many that protect the living body from the deleterious effects of free radicals.
APOE4: A variety of the APOE gene, that codes for the protein apolipoprotein E. The E4 variety is found in a quarter of the general population and associated with an increased risk of Alzheimer’s disease.
Baseline: A set of data collected at the beginning of a study.
Basic activities of daily living: The ability to perform activities that are fundamental for functioning such as feed oneself, get in and out of bed, use the lavatory, dress and undress, wash and bath oneself, and walk between rooms.
Beta-carotene: An isomer (form variety) of carotene that is found in dark green and dark yellow vegetables and fruits; precursor for vitamin A, acts as antioxidant.
Blood pressure: Pressure exerted by the blood upon the walls of the blood vessels, especially arteries.
BMI: Weight in kilograms divided by the square of height in meters. This measure, suggested by the Belgian scientist Lambert Adolphe Jacques Quetelet, correlates closely with body density and skinfold thicknesses. It is a standard measure for the purpose of detecting excess weight and obesity.
Body fatness: The amount of body fat obtained by underwater weighing and indicated by skinfold thicknesses and waist circumference.
B-vitamins: A group of water-soluble vitamins that play important roles in cell metabolism. The B-vitamins were once thought to be a single vitamin, referred to as vitamin B. Later research showed that they are chemically distinct vitamins that often coexist in the same foods.
Cardiovascular disease (CVD): Any disease that affects the heart or blood vessels (arteries, capillaries and veins), principally cardiac disease, vascular diseases of the brain, and peripheral arterial disease.
Cholesterol: A steroid alcohol (C27H45OH) present in animal cells and body fluids that regulates membrane fluidity, functions as a precursor molecule in various metabolic and endocrine pathways and as a constituent of LDL may cause atherosclerosis.
Cognitive decline: The deterioration of mental processes like memory, learning, language, thinking and judgment.
Cognitive function: Any mental process that involves symbolic operations, e.g. perception, memory, creation of imagery, and thinking. Cognitive function also encompasses awareness and capacity for judgment.
Cognitive health: A normal level of functioning in mental processes, e.g. memory, learning, language, thinking and judgment.
Cohort: Any designated group of persons that is studied over a period of time (as in a cohort study), so that its characteristics (e.g., causes of death and numbers still living) can be determined as time and age unravels.
Coronary heart disease (CHD): A condition especially caused by atherosclerosis and thrombosis that reduces the blood flow through the coronary arteries to the heart muscle and typically results in chest pain or heart damage.
Correlation: The degree to which variables vary together. It resembles how closely two (or more) variables are related. A causal connection between correlated variables is not necessary.
Cross-check dietary history: A dietary survey method to estimate the habitual food consumption of individuals. The interview consists of three steps. First, information is collected about the usual food consumption pattern during weekdays or weeks. This is checked by collecting information on the average consumption of foods during a day or a week. The second check consists or either a 3-day record or estimating the quantity of food bought for the whole family during a week.
Cross-cultural study: An observational study in which populations from different cultural backgrounds are compared.
Dementia: A usually progressive condition marked by the development of multiple cognitive deficits (such as memory impairment, aphasia, and inability to plan and initiate complex behavior).
Depressive symptoms: Feelings or behaviors related to the depressive disorder. These include but are not limited to: feelings of sadness, reduced interest and pleasure in almost all activities, insomnia, slowed thinking, and loss of appetite.
Dietary fiber: Constituents of plant cells that can not be digested or absorbed in the human stomach and small intestine, particularly pectin, cellulose, hemicellulose, and lignin.
Dietary survey: A way of researching the food consumption of individuals or groups. These may include questionnaires, a food diary, intake weighing and chemical analysis of foods.
Disability: Temporary or long-term reduction of a person’s capacity to function.
Dispositional optimism: A disposition that represents the extent to which people have positive, confident expectations about their own future outcomes, and/or the extent to which a person typically adopts an optimistic or pessimistic approach to dealing with life’s challenges.
Docosahexaenoic acid (DHA): An omega-3 fatty acid (C22H34O2) found especially in fish oils. The molecule contains 6 double bonds (C=C) with the first one at the third carbon atom, making it a polyunsaturated fatty acid.
ECG predictors: Characteristics of the electrocardiogram that are indicative of conduction disturbances (e.g., arrhythmia, tachycardia), coronary heart disease, or occlusion sites in the heart’s blood vessels.
Endothelial function: The extent to which the lining of the blood vessels exert their normal task of a.o. controlling vascular relaxation and blood clotting. Dysfunction of the endothelial membrane has been shown to be a predictor of stroke and heart attacks, because vessel dilatation is impaired.
Electrocardiography: An instrument for recording the changes of electrical potential occurring during the heartbeat used especially in diagnosing abnormalities of heart action.
Eicosapentaenoic acid (EPA): An omega-3 fatty acid (C20H30O2) found especially in fish oils. The molecule contains 5 double bonds (C=C) with the first one at the third carbon atom, making it a polyunsaturated fatty acid.
Epicatechin: One of the 5 major monomeric flavan-3-ols.
Epidemiology: The study of the occurrence and distribution of health-related states or events in specified populations, including the study of the determinants influencing such states, and the application of this knowledge to control the health problems.
Fatty acids: Any of the saturated or unsaturated organic acids that have a single carboxyl acid group and usually an even number of carbon atoms and that occur naturally in the form of (tri)glycerides in fats and oils.
Flavan-3-ols (catechins): A subclass of the flavonoids with the following specific molecular skeleton: 2-phenyl-3,4-dihydro-2H-chromen-3-ol. Procyanidins are formed through condensation of flavan-3-ols into oligomers. Tea, apples and cocoa are rich sources of flavan-3-ols.
Flavonoids: Large class of compounds ubiquitous in plant foods characterised by two benzene rings bridged by a chain of three carbon atoms forming a heterocyclyc 6-membered ring with oxygen and two carbon atoms from an adjacent benzene ring. The benzene rings contain one or more hydroxyl groups (phenolic groups), which causes their antioxidant properties. They include many common red and blue pigments.
Flavonols: A subclass of the flavonoids with the following specific molecular skeleton: 2-phenyl-3,4-dihydro-2H-chromen-3-ol, but also featuring a ketone group. Rich sources of flavonols are tea, apples and onions.
Follow-up: Observation over a period of time of an individual, group, or an initially defined population whose appropriate characteristics have been assessed in order to observe changes in health status or health-related variables.
Functional status: An individual’s ability to perform normal daily activities required to meet basic needs, fulfill usual roles, and maintain health and well-being. Decline in functional status is measured by an individual’s loss of independence in activities of daily living over a period of time.
Genotype: The genetic constitution inherited by an organism or a person. The genotype of an organism is finally expressed as a phenotype, in which the environment also has influence on its taking shape.
Glucose tolerance: The body’s ability to metabolize glucose.
HDL-cholesterol: A lipoprotein in blood plasma that is composed of a high proportion of protein with little triglyceride and cholesterol and which concentration is associated with a decreased probability of developing coronary heart disease.
Healthy Diet Indicator (HDI) score: The HDI is based on WHO guidelines for the prevention of chronic diseases. If a person´s intake was within the recommended borders this variable was coded 1 and if the intake was outside these borders, it was coded 0, e.g. a polyunsaturated fatty acid intake of 3-7 % energy was coded as 1 and an intake below 3 or higher than 7 as 0. The HDI was calculated as the sum of 9 dichotomous variables (range 0-9).
Heterogeneity: Statistical heterogeneity is based on interaction and shows that in subgroups of the population the strengths of the associations of an exposure with an outcome are distinctly different.
Hydrogenated oils: A processed variety of oils rich in polyunsaturated fatty acids (containing more than one carbon-carbon double bonds (C=C)).
Hypercholesterolemia: The presence of excess cholesterol in the blood and is usually indicated as an adult level of at least 5 mmol/L or 200 mg/100 ml. Hypercholesterolemia is a risk factor of coronary heart disease.
Hypertension: An elevated arterial blood pressure that is usually indicated by an adult systolic blood pressure of at least 140 mm Hg or a diastolic blood pressure of at least 90 mm Hg. It may result in thickening and inelasticity of the arterial walls and hypertrophy of the left heart ventricle. Hypertension is a risk factor for various pathological conditions and cardiovascular events (e.g. heart attack, heart failure, stroke, end-stage renal disease, or retinal hemorrhage).
Incidence: The number of instances of illness commencing, or of persons falling ill, during a given period in a specified population. More generally it is the number of new health-related events in a defined population within a specified period of time. It may be measured as a frequency count, a rate, or a proportion.
Indicator of disease: In statistics it is a variable taking only one of two possible values, one indicating the presence of a condition (usually 1), and the other indicating absence of the condition (usually zero).
Inflammation: A local and global response to cellular injury. Locally it is marked by capillary dilatation, leukocytic infiltration, redness, heat, pain, swelling, and often loss of function, while globally it may be marked by increased circulating levels of acute phase proteins and pro-inflammatory cytokines, and fever. It serves as a mechanism initiating the elimination of noxious agents and of damaged tissue.
Instrumental activities of daily living: The ability to perform activities that are not fundamental for functioning, but allow an individual to live independently in a community. Examples are housework, shopping, managing money and using technology and transportation.
Insulin: A hormone that is synthesized in the pancreas from proinsulin. It is essential for the metabolism of carbohydrates and lipids, and it regulates blood sugar levels by facilitating the uptake of glucose into tissues. It does so by promoting its conversion into glycogen, fatty acids, and triglycerides. When produced in insufficient quantities it results in type I or II diabetes mellitus.
J-shaped relation: A non-linear relationship between two variables that is described by a curve that initially falls, but then rises to become higher than the starting point.
LDL cholesterol: A lipoprotein in blood plasma that is composed of a moderate proportion of protein with little triglyceride and a high proportion of cholesterol. Its concentration is associated with an increased probability of developing coronary heart disease.
LDL oxidation: The process in which the use of oxygen causes electrons to be lost from LDL molecules and makes them unstable or reactive. Oxidized LDL promotes atherosclerosis.
Lignans: Any of a class of propyl phenolic dimeric molecules. Many are found in plants and noted for having antioxidant and estrogenic activity.
Longitudinal analysis: An analysis in which the population of interest is studied over time. See also cohort (study).
Lung function: Is expressed by diverse measures of the respiratory system. Pulmonary mechanics can be tested by spirometry, that includes the total volume of air that can be inhaled or expired, and the maximum speed with which in- and exhalation occurs.
Mediterranean Adequacy Index (MAI): An index score based on typical Mediterranean foods: bread, cereals, legumes, potatoes, vegetables, fruit, vegetable oils, fish and red wine and on non-typical Mediterranean foods: milk, cheese, eggs, meat, animal fats and margarines, sugar, cakes, pies and cookies.
Mediterranean Diet Score (MDS): A score indicating compliance to the Mediterranean diet. A high intake of the Mediterranean foods: cereals, legumes, fruits, vegetables, olive oil and fish were scored positive (1) and and a high intake of the non-Mediterranean foods: dairy and meat negative (0). The score ranged from 0 to 9 and the higher the score the better the compliance to a traditional Mediterranean diet.
Meta-analysis: A statistical analysis of the results from separate studies, examining sources of differences among studies. A frequent application is the pooling of results from a set of prospective cohort studies, which in aggregate have more statistical power to detect associations at conventional levels of statistical significance than individual studies.
mmol/L: Stands for millimole per liter. A mole is a measure of quantity based on the number of molecules rather than weight, and so mmol/L can be used as a measure of a solution of, for example, glucose in blood.
Mobility-related activities of daily living: The ability to perform activities such as moving outdoors, using stairs, walking at least 400 meters, and carrying a heavy object for 100 meters.
Morbidity: Any departure, subjective or objective, from a state of physiological or psychological well-being. In this sense sickness, illness, and morbid condition are similarly defined and synonymous.
Mortality: An estimate of the number for persons in a population who died in a specified period.
Multifactorial disease: A condition caused by many contributing factors and they may be genetic, lifestyle or environmental factors, or a combination of any of those.
Multivariable modeling: A set of techniques used when several risk factors have to be studied simultaneously in relation to the occurrence of disease. In statistics it is any analytical method that allows the simultaneous study of two or more independent variables in relation to dependent variable(s).
Obesity: A condition that is characterized by excessive accumulation and storage of fat in the body and is typically indicated by a body mass index of 30 kg/m2 or greater in adults.
Omega-3 fatty acids: Essential fatty acids commonly found in marine and plant oils. They are polyunsaturated fatty acids with a double bond (C=C) starting after the third carbon atom from the terminal carbon group.
Optimism: Optimism is conceptualized in at least two ways. Dispositional optimism (see also Dispositional optimism) is the general expectancy of positive outcomes, while explanatory style optimism refers to whether a person believes that he or she has control or influence over events (with an optimistic person explaining the causes of negative events as external, unstable and specific).
Oxidative stress: Physiological stress on the body that is caused by the cumulative damage from free radicals inadequately neutralized by antioxidants. It is considered to be associated with ageing.
Percent of energy: The proportion of total daily energy intake constituted by a macronutrient.
Physician-rated health: A judgment of the overall health status of a person by a physician based on a disease history and a physical examination. As opposed to: self-rated health.
Polymorphism: The occurrence in a population of two or more genotypes; i.e. the existence of two or more genetic variants. Genetic polymorphims can have opposite relations with different diseases.
Polyphenols: A very large class of naturally occurring phenolic compounds ubiquitous in plants, roughly estimated to contain more than 10.000 different compounds. The phenolic groups are responsible for the antioxidant properties of polyphenols. Flavonoids are one of the subgroups of this large family of compounds.
Polyunsaturated fat: A class of fats with long carbon chains and two or more double bonds (C=C) that are not saturated with hydrogen atoms. Polyunsaturated fats lower blood cholesterol when they replace saturated fats.
Population: All the inhabitants of a given country or area considered together. In research this means the whole collection of units (the “universe”) from which a sample may be drawn; not necessarily a population of persons – the units may also be institutions, records, or events. A random sample intends to provide results that are representative of the whole population.
Prevalence: A measure of disease occurrence: the total number of individuals who have an attribute or disease at a particular time (it may also be a particular period) divided by the population at risk of having the attribute or disease at that time or midway through the period. It is a proportion, not a rate.
Prospective study: A study in which a population is followed over time. See also cohort (study).
Protective association: The phenomenon in which a high level of a factor (e.g. dietary fiber intake) is associated with a low of e.g. CVD incidence. In that case the first factor is protective for the second.
Relative risk: The ratio of the incidence rate in the exposed to the incidence rate in those who are not exposed to a particular factor.
Risk factor: An aspect of personal behavior or lifestyle, an environmental exposure, or an inborn or inherited characteristic that, on the basis of scientific evidence, is known to be associated with meaningful health-related condition(s). It’s not necessarily a causal factor: it may be a risk marker, merely indicating a greater risk caused by something else.
Saturated fat: A fat that consists of triglycerides containing only saturated fatty acids. Saturated fatty acids have no double bonds between the individual carbon atoms of the fatty acid chain. That is, the chain of carbon atoms is fully “saturated” with hydrogen atoms.
Sedentary: Doing or requiring much sitting and is characterized by lack of physical activity.
Self-rated health: A subjective judgment of the overall health status by the person him- or herself. As opposed to: physician-rated health.
Serum: A yellowish fluid that remains from whole blood after cells and clotting factors have been removed by centrifugation.
Statistical significance: A statistical property of an observation or an estimate that is unlikely to have occurred by chance alone. A two-sided p-value < 0.05 is generally considered significant.
Standard deviation: A measure of dispersion or variation. It is the most widely used measure of dispersion of a frequency distribution. It is equal to the positive square root of the variance. The mean tells where the values for a group are centered. The standard deviation is a summary of how widely dispersed the values are around this center.
Stroke: Sudden diminution or loss of consciousness, sensation, and voluntary motion caused by rupture or obstruction (as by a clot) of a blood vessel of the brain.
Sudden cardiac death: The cause of death of those, who died within 2 hours after onset of symptoms with a high likelihood to be coronary and those with a past diagnosis of CHD.
Systolic blood pressure: The highest arterial blood pressure of a cardiac cycle occurring immediately after systole (contraction) of the left ventricle of the heart.
Telomere: The natural end of a chromosome composed of a usually repetitive (non-coding) DNA sequence (i.e., TTAGGG). It serves to stabilize the chromosome and protects against end-to-end fusion of DNA.
Trans fat: The common name for unsaturated fat with trans-isomer fatty acids. The term refers to the spatial configuration of a double carbon-carbon bond (C=C) and trans fats can be mono or polyunsaturated, but never saturated. Trans fats do exist in nature, mainly in ruminant fats, but also occur during partial hydrogenation of polyunsaturated fatty acids in food production.
Type II diabetes: Diabetes mellitus of a common disorder that develops especially in adults and most often in obese individuals and is characterized by hyperglycemia resulting from impaired insulin utilization, coupled with the body’s inability to compensate with increased insulin production.
Vitamin C: A water-soluble vitamin (C6H8O6) found in plants and especially in citrus fruits and leafy vegetables or made synthetically. Used in the prevention and treatment of scurvy and as an antioxidant for foods.
Vitamin E: Any of several fat-soluble vitamins whose lack in the human body is associated especially with neurological symptoms (e.g. ataxia and muscle weakness). They are found especially in wheat germ, vegetable oils, egg yolk, and green leafy vegetables or are made synthetically. Vitamin E is used chiefly in animal feeds and as antioxidant.
WHO: The World Health Organization (www.who.int) is a specialized agency of the United Nations (UN) and is concerned with international public health.