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Public health glossary

108 terms used across Vellora’s maps, tools and articles. Each definition links to the CDC, NIH or NCI page it is written from; definitions marked “Vellora note” explain how Vellora itself presents data.

108 terms

Age-adjusted rate
A weighted average of age-specific rates, using the age distribution of a standard population (usually the 2000 U.S. standard population). It removes differences that come only from age structure, so places with older or younger residents can be compared. Age-adjusted rates are relative indexes, not actual measures of risk.

Data and statisticsCDC National Center for Health Statistics: Age adjustment (Health, United States: Sources and Definitions)National Cancer Institute, SEER Program: Calculating Age-adjusted Rates

Association (correlation)
Vellora note: A tendency for two measures to rise or fall together across counties. Vellora reports Pearson (linear) and Spearman (rank) correlation. An association does not show that one measure causes the other; both may reflect age, income, access to care or other factors.

Data and statisticsMore in Methodology

Asthma attack
A worsening of symptoms in which airway walls swell, airways shrink and mucus clogs them, so less air moves in and out.

Health and medicineCenters for Disease Control and Prevention: About AsthmaNational Heart, Lung, and Blood Institute: Asthma — What Is Asthma?From Asthma

Behavioral Risk Factor Surveillance System (BRFSS)
CDC’s system of health-related telephone surveys, established in 1984, that collects state data on adults’ risk behaviors, chronic health conditions, health-care access and use of preventive services. It completes more than 400,000 adult interviews a year and is a data source for CDC PLACES.

Data and statisticsCenters for Disease Control and Prevention: About BRFSS

Benign tumor
A tumor that does not invade nearby tissue. Benign tumors can still be large or, in places like the brain, serious.

Health and medicineNational Cancer Institute: What Is Cancer?National Cancer Institute: Risk Factors for CancerFrom Understanding Cancer

Blood pressure
The force of circulating blood on the walls of the arteries. It is written as two numbers: systolic (measured when the heart beats, the highest pressure) over diastolic (between beats, the lowest), for example 120/80.

Health and medicineNational Cancer Institute: NCI Dictionary of Cancer Terms: blood pressure

Carcinoma in situ
Abnormal cells that have not invaded nearby tissue. Sometimes called stage 0; usually treated because it may become cancer.

Health and medicineNational Cancer Institute: What Is Cancer?National Cancer Institute: Risk Factors for CancerFrom Understanding Cancer

Chronic bronchitis
Long-term irritation and inflammation of the airway lining, with thick mucus that makes breathing hard.

Health and medicineCenters for Disease Control and Prevention: About COPDNational Heart, Lung, and Blood Institute: COPD — What Is COPD?From Chronic Obstructive Pulmonary Disease

Cognitive behavioral therapy (CBT)
A well-studied talk therapy that helps people notice and change unhelpful thought and behavior patterns.

Health and medicineNational Institute of Mental Health: Anxiety DisordersNational Institute of Mental Health: Generalized Anxiety Disorder: What You Need to KnowFrom Anxiety and Mental Health

Confidence interval (95% CI)
A range around an estimate that shows its uncertainty. For PLACES, CDC simulates each estimate 1,000 times and reports the 2.5th to 97.5th percentiles of the results as the 95% confidence interval. Wider intervals mean less certainty.

Data and statisticsCenters for Disease Control and Prevention: PLACES: Methodology

Controller and reliever medicines
Controller medicines help people have fewer and milder attacks; reliever medicines treat symptoms when they happen.

Health and medicineCenters for Disease Control and Prevention: About AsthmaNational Heart, Lung, and Blood Institute: Asthma — What Is Asthma?From Asthma

Coronary artery disease (CAD)
Narrowing of the arteries that supply the heart, caused by plaque buildup. Also called coronary heart disease or ischemic heart disease.

Health and medicineCenters for Disease Control and Prevention: About Heart DiseaseNational Heart, Lung, and Blood Institute: Coronary Heart Disease — What Is Coronary Heart Disease?From Understanding Cardiovascular Disease

Crude prevalence
The share of all adults with a condition, with no adjustment for age. Places with older residents tend to show higher crude prevalence of age-related conditions, so comparisons between areas should take differences in age structure into account.

Data and statisticsCenters for Disease Control and Prevention: PLACES: Frequently Asked QuestionsNational Cancer Institute, SEER Program: Calculating Age-adjusted RatesMore in Methodology

Degenerative disease
A disease in which nerve cells are damaged or die over time, such as Parkinson’s disease or Alzheimer’s disease.

Health and medicineMedlinePlus, U.S. National Library of Medicine: Neurologic Diseases (Nervous System Diseases)Centers for Disease Control and Prevention: About StrokeFrom Understanding Neurological Disorders

Diagnosed vs undiagnosed diabetes
Surveys that ask whether someone has been told they have diabetes miss people who have it but have not been tested.

Health and medicineCenters for Disease Control and Prevention: Type 2 DiabetesCenters for Disease Control and Prevention: Diabetes BasicsCenters for Disease Control and Prevention: National Diabetes Statistics ReportFrom Type 2 Diabetes and Population Health

Dysarthria and apraxia of speech
Speech disorders that can occur alongside aphasia.

Health and medicineNational Institute on Deafness and Other Communication Disorders: AphasiaFrom Aphasia and Neurological Communication Disorders

Dysarthria and dysphagia
Slurred speech, and difficulty chewing or swallowing.

Health and medicineU.S. National Library of Medicine: Amyotrophic lateral sclerosis — MedlinePlus GeneticsFrom Amyotrophic Lateral Sclerosis (ALS)

Ecological comparison
Vellora note: A comparison of places rather than people. A pattern across counties describes the counties as a whole and cannot show what is true for any one person living in them.

Data and statistics

Edema
Swelling — often in the legs, feet or ankles — that can occur when the kidneys cannot remove extra fluid and salt.

Health and medicineCenters for Disease Control and Prevention: Chronic Kidney Disease BasicsNational Institute of Diabetes and Digestive and Kidney Diseases: What Is Chronic Kidney Disease in Adults?From Chronic Kidney Disease

Elevated blood pressure
Blood pressure slightly higher than normal but not yet high blood pressure: a systolic (top) number of 120–129 mm Hg and a diastolic (bottom) number below 80 mm Hg. Over time it can progress to high blood pressure.

Health and medicineCenters for Disease Control and Prevention: High Blood Pressure Risk Factors

Emphysema
Damage to the walls between the lungs’ air sacs, making it harder to move air out of the lungs.

Health and medicineCenters for Disease Control and Prevention: About COPDNational Heart, Lung, and Blood Institute: COPD — What Is COPD?From Chronic Obstructive Pulmonary Disease

Familial ALS
ALS that runs in families; estimated at about 5% to 10% of cases.

Health and medicineU.S. National Library of Medicine: Amyotrophic lateral sclerosis — MedlinePlus GeneticsFrom Amyotrophic Lateral Sclerosis (ALS)

Fluent aphasia
Speech flows in long sentences but may carry little meaning; Wernicke’s aphasia is the best-known type and often includes difficulty understanding language.

Health and medicineNational Institute on Deafness and Other Communication Disorders: AphasiaFrom Aphasia and Neurological Communication Disorders

Frontotemporal dementia (FTD)
A progressive brain disorder affecting personality, behavior and language that develops in some people with ALS.

Health and medicineU.S. National Library of Medicine: Amyotrophic lateral sclerosis — MedlinePlus GeneticsFrom Amyotrophic Lateral Sclerosis (ALS)

Generalized anxiety disorder (GAD)
Excessive, hard-to-control worry on most days for at least 6 months, with symptoms such as restlessness, fatigue, poor concentration, irritability, muscle tension or sleep problems.

Health and medicineNational Institute of Mental Health: Anxiety DisordersNational Institute of Mental Health: Generalized Anxiety Disorder: What You Need to KnowFrom Anxiety and Mental Health

Gestational diabetes
Diabetes that develops during pregnancy. It usually goes away after birth but raises the later risk of type 2 diabetes.

Health and medicineCenters for Disease Control and Prevention: Diabetes BasicsNational Institute of Diabetes and Digestive and Kidney Diseases: What Is Diabetes?From Understanding Diabetes

Global aphasia
Severe difficulty producing and understanding language after extensive damage to language areas.

Health and medicineNational Institute on Deafness and Other Communication Disorders: AphasiaFrom Aphasia and Neurological Communication Disorders

Health disparity
A type of preventable health difference closely linked with social, political, economic and environmental disadvantage. Disparities may occur by race, ethnicity, sex, age, disability, education, income, where people live or other characteristics.

Data and statisticsNational Cancer Institute: NCI Dictionary of Cancer Terms: health disparity

Health Professional Shortage Area (HPSA)
A federal designation that directs limited resources to communities with the greatest need for primary care, dental or mental health services.

Health and medicineNational Institute of Mental Health: Mental Illness (statistics)Centers for Disease Control and Prevention: About Mental HealthHealth Resources and Services Administration: Health Workforce Shortage AreasFrom Mental Health Access and Population Trends

Hemorrhagic stroke
An artery in the brain leaks or ruptures, and the leaked blood damages brain cells.

Health and medicineCenters for Disease Control and Prevention: About StrokeCenters for Disease Control and Prevention: About High Blood PressureFrom Stroke and Cardiovascular Risk

Hypertension (high blood pressure)
Blood pressure that is consistently at or above 130/80 mm Hg; normal is less than 120/80 mm Hg. Most people with hypertension have no signs or symptoms, so measuring blood pressure is the only way to know.

Health and medicineCenters for Disease Control and Prevention: About High Blood PressureFrom High Blood Pressure (Hypertension)

Incidence
The number of new cases of a characteristic that develop in a population in a specified time period. Prevalence counts everyone who has a condition; incidence counts only new cases.

Data and statisticsNational Institute of Mental Health: What is Prevalence?

Ischemic stroke
The most common type: a blood clot or other particle blocks a blood vessel to the brain.

Health and medicineCenters for Disease Control and Prevention: About StrokeCenters for Disease Control and Prevention: About High Blood PressureFrom Stroke and Cardiovascular Risk

Kidney failure / end-stage kidney disease (ESKD)
When the kidneys stop working and dialysis or a kidney transplant is needed to survive.

Health and medicineCenters for Disease Control and Prevention: Chronic Kidney Disease BasicsNational Institute of Diabetes and Digestive and Kidney Diseases: What Is Chronic Kidney Disease in Adults?From Chronic Kidney Disease

Low-dose CT (LDCT)
A scan that uses a small amount of radiation to make detailed images of the lungs; the recommended lung cancer screening test.

Health and medicineMedlinePlus, U.S. National Library of Medicine: Lung CancerCenters for Disease Control and Prevention: Lung Cancer Risk FactorsCenters for Disease Control and Prevention: Screening for Lung CancerFrom Lung Cancer

Major depression
Depressed mood or loss of interest, most of the time for at least 2 weeks, that interferes with daily activities.

Health and medicineNational Institute of Mental Health: Depression (publication)From Depression

Metabolic syndrome
A group of conditions — at least three of large waist size, high triglycerides, high blood pressure, high fasting blood glucose and low HDL (“good”) cholesterol — that raises the risk of heart disease, diabetes and stroke.

Health and medicineNational Institute of Diabetes and Digestive and Kidney Diseases: Health Risks of Overweight & ObesityFrom Obesity and Chronic Disease

Metastasis
The spread of cancer cells from where they first formed to other parts of the body. Breast cancer that spreads to the lung is still breast cancer.

Health and medicineNational Cancer Institute: What Is Cancer?National Cancer Institute: Risk Factors for CancerFrom Understanding Cancer

Mortality (death rate)
The number of deaths in a certain group of people in a certain period of time. It may be reported for people with a certain disease, for one area, or by sex, age or ethnic group.

Data and statisticsNational Cancer Institute: NCI Dictionary of Cancer Terms: mortality

Motor neuron
A nerve cell in the brain or spinal cord that controls muscle movement.

Health and medicineU.S. National Library of Medicine: Amyotrophic lateral sclerosis — MedlinePlus GeneticsFrom Amyotrophic Lateral Sclerosis (ALS)

Nonfluent aphasia
Short, effortful phrases that leave out small words; Broca’s aphasia is the best-known type.

Health and medicineNational Institute on Deafness and Other Communication Disorders: AphasiaFrom Aphasia and Neurological Communication Disorders

Normal blood pressure
Systolic less than 120 and diastolic less than 80 mm Hg.

Health and medicineCenters for Disease Control and Prevention: About High Blood PressureFrom High Blood Pressure (Hypertension)

Obesity
BMI 30 or greater — Class 1 (30 to <35), Class 2 (35 to <40) and Class 3 or severe obesity (40 or greater)

Health and medicineCenters for Disease Control and Prevention: Adult BMI CategoriesCenters for Disease Control and Prevention: Adult Obesity FactsFrom Understanding Obesity as a Public Health Indicator

Observed outcome
Vellora note: A figure counted from records, such as deaths from death certificates or cancer cases from a registry, rather than estimated from a survey model. Observed rates still carry uncertainty, especially for small counties.

Data and statisticsMore in Methodology

Other anxiety disorders
Panic disorder, social anxiety disorder and various phobia-related disorders.

Health and medicineNational Institute of Mental Health: Anxiety DisordersNational Institute of Mental Health: Generalized Anxiety Disorder: What You Need to KnowFrom Anxiety and Mental Health

Pack-year
Smoking an average of one pack of cigarettes a day for one year. One pack a day for 20 years, or two packs a day for 10 years, both equal 20 pack-years.

Health and medicineMedlinePlus, U.S. National Library of Medicine: Lung CancerCenters for Disease Control and Prevention: Lung Cancer Risk FactorsCenters for Disease Control and Prevention: Screening for Lung CancerFrom Lung Cancer

Percentage point
Vellora note: The unit for the gap between two percentages. A change from 9% to 12% is 3 percentage points, which is a 33% relative increase.

Data and statistics

Perinatal depression
Depression during pregnancy or after childbirth; more than the “baby blues.”

Health and medicineNational Institute of Mental Health: Depression (publication)From Depression

Persistent depressive disorder (dysthymia)
Less severe depression symptoms that last much longer, usually at least 2 years.

Health and medicineNational Institute of Mental Health: Depression (publication)From Depression

Prediabetes
Blood glucose that is higher than normal but not high enough for a type 2 diagnosis.

Health and medicineCenters for Disease Control and Prevention: Diabetes BasicsNational Institute of Diabetes and Digestive and Kidney Diseases: What Is Diabetes?From Understanding Diabetes

Prevalence
The share of a population who have a specific characteristic, such as a health condition, in a given time period, regardless of when they first developed it. It is reported as a percentage or as cases per 10,000 or 100,000 people.

Data and statisticsNational Institute of Mental Health: What is Prevalence?

Primary progressive aphasia (PPA)
Aphasia that is the first and most noticeable sign of dementia and worsens over time.

Health and medicineNational Institute on Deafness and Other Communication Disorders: AphasiaFrom Aphasia and Neurological Communication Disorders

Psychotherapy
Talk therapy or counselling that teaches new ways of thinking and behaving.

Health and medicineNational Institute of Mental Health: Depression (publication)From Depression

Pulmonary rehabilitation
A personalized program that teaches people with COPD to breathe better, conserve energy and choose suitable food and activity.

Health and medicineCenters for Disease Control and Prevention: About COPDNational Heart, Lung, and Blood Institute: COPD — What Is COPD?From Chronic Obstructive Pulmonary Disease

Quantile (quintile)
A set of categories that each hold approximately the same number of items; quintiles are five such groups.

Data and statisticsCenters for Disease Control and Prevention: Atlas of Heart Disease and Stroke: Statistical MethodsMore in Methodology

Radon
A naturally occurring radioactive gas from rocks, soil and water that cannot be seen, smelled or tasted and can build up indoors.

Health and medicineMedlinePlus, U.S. National Library of Medicine: Lung CancerCenters for Disease Control and Prevention: Lung Cancer Risk FactorsCenters for Disease Control and Prevention: Screening for Lung CancerFrom Lung Cancer

Risk factor
Something that increases the chance of developing a disease.

Health and medicineNational Cancer Institute: NCI Dictionary of Cancer Terms: risk factor

Seasonal affective disorder
Depression that comes and goes with the seasons, typically starting in late fall and early winter.

Health and medicineNational Institute of Mental Health: Depression (publication)From Depression

Severe hypertension
Systolic higher than 180 and/or diastolic higher than 120 mm Hg. With symptoms such as chest pain, shortness of breath, back pain, numbness, weakness, a change in vision or difficulty speaking, it is a hypertensive emergency: call 911.

Health and medicineCenters for Disease Control and Prevention: About High Blood PressureFrom High Blood Pressure (Hypertension)

Small area estimate (modeled estimate)
An estimate for a small area such as a county, produced by a statistical model rather than a direct count. CDC PLACES uses multilevel regression and poststratification (MRP): a model fitted to BRFSS survey responses, with census and American Community Survey data, predicts the probability of each outcome and applies it to each county’s adult population.

Data and statisticsCenters for Disease Control and Prevention: PLACES: Methodology

Spatial smoothing
A technique that makes rates more statistically reliable and stable for counties with small populations by borrowing information from neighbouring areas. CDC’s county heart disease death rates use a Local Empirical Bayes method.

Data and statisticsCenters for Disease Control and Prevention: Atlas of Heart Disease and Stroke: Statistical Methods

Spirometry
A breathing test that measures how much air a person can breathe out after a deep breath, often before and after asthma medicine.

Health and medicineCenters for Disease Control and Prevention: About AsthmaNational Heart, Lung, and Blood Institute: Asthma — What Is Asthma?From Asthma

Sporadic ALS
ALS in a person with no apparent family history of the disease; most people with ALS have this form.

Health and medicineU.S. National Library of Medicine: Amyotrophic lateral sclerosis — MedlinePlus GeneticsFrom Amyotrophic Lateral Sclerosis (ALS)

Stage 1 hypertension
Systolic 130–139 or diastolic 80–89 mm Hg.

Health and medicineCenters for Disease Control and Prevention: About High Blood PressureFrom High Blood Pressure (Hypertension)

Stage 2 hypertension
Systolic 140 or higher, or diastolic 90 or higher.

Health and medicineCenters for Disease Control and Prevention: About High Blood PressureFrom High Blood Pressure (Hypertension)

Stress
The physical or mental response to an external cause, such as a heavy workload or an illness.

Health and medicineNational Institute of Mental Health: Anxiety DisordersNational Institute of Mental Health: Generalized Anxiety Disorder: What You Need to KnowFrom Anxiety and Mental Health

Suppressed value
Vellora note: A value the source withholds, usually because the population or count is too small for a reliable estimate. Vellora shows suppressed counties hatched, with the source’s reason, and never treats them as zero.

Data and statisticsMore in Methodology

Systolic and diastolic
The two numbers of a blood pressure reading, in millimetres of mercury (mm Hg): systolic is the top number, diastolic the bottom.

Health and medicineCenters for Disease Control and Prevention: About High Blood PressureFrom High Blood Pressure (Hypertension)

Transient ischemic attack (TIA)
Often called a “mini-stroke”: blood flow to the brain is blocked for a short time, usually no more than 5 minutes. It is a warning sign and a medical emergency.

Health and medicineCenters for Disease Control and Prevention: About StrokeCenters for Disease Control and Prevention: About High Blood PressureFrom Stroke and Cardiovascular Risk

Trigger
Something that sets off or worsens asthma symptoms, such as pollen, exercise, viral infections or cold air.

Health and medicineCenters for Disease Control and Prevention: About AsthmaNational Heart, Lung, and Blood Institute: Asthma — What Is Asthma?From Asthma

Tumor
A lump of tissue formed by abnormal cells. Tumors can be cancerous (malignant) or not cancerous (benign).

Health and medicineNational Cancer Institute: What Is Cancer?National Cancer Institute: Risk Factors for CancerFrom Understanding Cancer

Type 1 diabetes
The body makes little or no insulin, thought to be caused by an autoimmune reaction. People with type 1 need insulin every day.

Health and medicineCenters for Disease Control and Prevention: Diabetes BasicsNational Institute of Diabetes and Digestive and Kidney Diseases: What Is Diabetes?From Understanding Diabetes

Type 2 diabetes
The body does not use insulin well and cannot keep blood glucose in the normal range. It is the most common type — about 90% to 95% of diagnosed cases.

Health and medicineCenters for Disease Control and Prevention: Diabetes BasicsNational Institute of Diabetes and Digestive and Kidney Diseases: What Is Diabetes?From Understanding Diabetes

General terms were checked against their sources on 2026-10-22. Medical terms come from the Key definitions of Vellora’s articles and carry those articles’ citations.

Vellora provides general education, not diagnosis or treatment advice. For personal health questions, consult a qualified health professional. In an emergency, call 911.