Epidemiology, Physical Activity, Obesity, and Chronic Disease

Comprehensive flashcard deck covering epidemiology, physical activity trends, lipid profiles, obesity BMI classifications, diabetes mechanisms, and bone health based on class notes.

What percentage of the population was physically inactive in 2017 according to the notes?

About $27.6\%$ of the population ($82.4\,\text{million}$ people) was inactive in 2017.

What shift in physical activity participation was identified as the biggest concern?

The shift from highly active participants toward casual or less frequent activity.

How do physical activity preferences and inactivity rates vary between younger people and older adults?

Younger people tended to participate more in team and outdoor sports, whereas older adults favored fitness activities and had the highest inactivity rate.

Who is recognized as the father of epidemiology, and how did he trace the cholera outbreak?

John Snow is recognized as the father of epidemiology; he and his team mapped cholera cases and discovered that most were clustered around a single water supply.

What are the four primary purposes for which epidemiology was established?

Epidemiology was established to: 1) describe, 2) explain, 3) predict, and 4) control health phenomena.

How is epidemiology defined in the lecture notes?

Epidemiology is the study of the distribution and determinants of health phenomena, diseases, and mortality in and across populations.

What does frequency measure in epidemiology, and what three patterns help describe frequencies?

Frequency is the number of cases or occurrences (which helps determine the rate of occurrence across populations). The three patterns used to describe frequencies are time, place, and person.

How are determinants or risk factors defined in epidemiology?

Determinants or risk factors are things capable of bringing about a disease or change in health, such as causes, factors, or events.

What is the distinction between morbidity and mortality?

Mortality designates death, while morbidity designates illness.

Why does epidemiology establish correlations rather than direct cause-and-effect relationships on its own?

Epidemiology is data-driven and identifies correlations; inferring cause-and-effect relationships requires a controlled experiment.

Which scientific fields contribute to the interdisciplinary nature of epidemiology?

Epidemiology relies on scientific expertise and methods from statistics, biology, informatics, economics, social science, and behavioral science.

What are the two primary goals of epidemiology listed in the notes?

1) To improve our understanding of the natural history of disease/health and the factors that influence disease/health distribution; 2) To develop successful interventions that consistently and effectively improve health outcomes for the population.

What are the key epidemiological findings regarding life expectancy and leading causes of death in the US?

Women live longer than men, Heart Disease (HD) and Cancer are the leading causes of death (lifestyle-related), and the average life expectancy of a US citizen is among the lowest.

Which health conditions are listed as being contributed to by physical inactivity?

Heart Disease (HD), obesity, hypertension, diabetes, hyperlipidemia, stroke, atherosclerosis, cancer, and osteoporosis.

What proportion of the population follows government dietary guidelines, and what percentages meet exercise recommendations?

Less than $1\%$ of the population follows government healthy diet recommendations (unhealthy diet is the most common health behavior). For exercise, $50\text{--}60\%$ get enough cardio, $20\%$ get enough strength training, and over $75\%$ do not get proper exercise.

Which health metrics commonly become prominent issues after age $50$?

Cholesterol, blood pressure, and diabetes.

What demographic patterns are associated with physical activity levels and fitness?

People with higher education tend to be more active due to accessibility, and white males over $18\,\text{years}$ old are the most fit/healthy.

What are the characteristics and high-risk threshold for LDL cholesterol?

LDL (low-density lipoprotein) is 'bad' cholesterol that moves lipids and contributes to atherosclerosis. An LDL level over $130\,\text{mg/dL}$ is considered high ('lousy') and runs into CVD/HD.

What are the characteristics and protective threshold for HDL cholesterol?

HDL (high-density lipoprotein) is 'good' cholesterol that helps recycle and distribute LDL better. An HDL level over $60\,\text{mg/dL}$ is high ('healthy') and protects against HD. HDL can be increased by exercise/physical activity.

At what total cholesterol level does the rate of CVD and HD increase?

A total cholesterol level over $240\,\text{mg/dL}$ increases the rate of CVD and HD.

What waist circumference measurements signify elevated abdominal fat and disease risk for men and women?

Greater than $40\,\text{in}$ for men and greater than $35\,\text{in}$ for women.

What waist-to-hip ratio thresholds indicate increased risk for heart disease?

A waist circumference to hip circumference ratio of $\ge 1.0$ for men and $\ge 0.8$ for women.

What are the BMI classifications for underweight, normal weight, overweight, and the three classes of obesity?

Underweight: $< 18.5\,\text{kg/m}^2$; Normal: $18.5\text{--}24.9\,\text{kg/m}^2$; Overweight: $25.0\text{--}29.9\,\text{kg/m}^2$; Obesity Class I: $30.0\text{--}34.9\,\text{kg/m}^2$; Obesity Class II: $35.0\text{--}39.9\,\text{kg/m}^2$; Extreme Obesity Class III: $\ge 40.0\,\text{kg/m}^2$.

How do dieting and exercise compare in achieving weight loss and controlling obesity?

Dieting outperforms exercise for initial weight loss, but combining diet with exercise enhances weight loss. Because lost body weight is normally regained, controlling weight over time (e.g., through walking) is best. Exercise alone is not a good solution to obesity.

Which racial or ethnic groups show the highest and lowest rates of obesity?

Hispanic and Latino populations have the highest rate of obesity in children and adults, whereas Asian populations are less likely to become obese.

How does consuming too many calories affect cells and glucose channels, and how does exercise reverse this?

When cells are overfed from too many calories, glucose channels are removed, causing glucose to age and stick to neurons and kidneys. Exercise empties glucose out of cells and leads to good blood sugar readings.

What proportion of diabetes cases are Type II, and what is its physiological mechanism?

Type II accounts for $90\%$ of diabetes cases. It is a chronic disease where the body is unable to use insulin, causing blood sugar levels to rise to dangerous levels.

What is the difference between osteoporosis and osteopenia?

Osteoporosis is abnormally low bone mass characterized by brittle bones and an increased fracture rate. Osteopenia is 'pre-osteoporosis' where bone mass is not critically low but causes injury and serves as a risk factor for osteoporosis.

Which types of physical activity are specifically recommended to protect bone health?

Resistance training appears impactful for osteoporosis risk, and walking has been shown to preserve bone mineral density in the lower limbs and axial skeleton.