Table 1.

Operational Definition of Measured Variables

DEPENDENT VARIABLES	Operational Definition of Variables †
1. Physical activity: This variable indicates whether respondents met the 2018 physical activity guidelines for aerobic activity. Inactive: no activity; Insufficiently active: <150 min/week; Sufficiently active: 150+ min/week	○ Inactive/Insufficiently active [0] ○ Sufficiently active [1] §
2. Frequency of walking near home: How often does the walking you reported earlier take place near home?	○ Never/Some of the time [0] ○ Most of the time/Almost always [1] §
3. Body mass index: Continuous variables	○ BMI was created from height and weight values. BMI was calculated using the formula: BMI = kilograms/meters2 where 1 kilogram = 2.20462 pounds and 1 meter = 39.37008 inches.
EXPOSURE
Perceived walkability is a sum of eight dichotomous variables (Continuous)	○ 0–8
1. Where you live, are there roads, sidewalks, paths, or trails where you can walk?	○ No [0] ○ Yes [1]
2. Are there shops, stores, or markets that you can walk to?	○ No [0] ○ Yes [1]
3. Are there bus or transit stops that you can walk to?	○ No [0] ○ Yes [1]
4. Are there places like movies, libraries, or places of worship that you can walk to?	○ No [0] ○ Yes [1]
5. Are there places that you can walk to that help you relax, clear your mind, and reduce stress?	○ No [0] ○ Yes [1]
6. Where you live, do most streets have sidewalks?	○ No [0] ○ Yes [1]
7. Does traffic make it unsafe for you to walk? Reverse coded	○ No [0] ○ Yes [1]
8. Does crime make it unsafe for you to walk? Reverse coded	○ No [0] ○ Yes [1]
Perceived walkability (Categorical)
Low	○ Scores of 0–2
Medium	○ Scores of 3–5
High	○ Scores of 6–8
INDEPENDENT VARIABLES
Age in years	Continuous (50–85+)
Biological sex	○ Male [0] §Female [1]
Race/Ethnicity	○ Non-Hispanic White [0] § Racial/Ethnic minorities (Non-Hispanic Black, Non-Hispanic Asian, Non-Hispanic American Indian/Alaska Native, Non-Hispanic other race, Hispanic)
Marital status	○ Single/Widowed/Separated [0] ○ Married/Partnered [1] §
Education level	○ < Bachelor’s degree [0] § ○ ≥ Bachelor’s degree [1]
Urban-rural classification	○ Large central metro [1] § ○ Large fringe metro [2] ○ Medium and small metro [3] ○ Non-metropolitan [4]
Region	○ Northeast [1] § ○ Midwest [2] ○ South [3] ○ West [4]
Employment status	○ Not employed last week or the past year/never [0] § ○ Employed last week or the past year [1]
Federal poverty level ††	○ <=138 % [1] § ○ >138–250 % [2] ○ >250–400 % [3] ○ >400 % [4]
Total chronic diseases: Respondents answered “Yes” to having any of these diseases	Obesity, hypertension, type 2 diabetes, asthma, arthritis, COPD, hepatitis, coronary heart diseases, stroke, heart attack, angina, dementia, cirrhosis, kidney failure
Self-reported health status	○ Excellent [1] § Very good [2] ○ Good [3] ○ Fair/Poor [4]

Source: National Health Interview Survey (NHIS, 2020). National Center for Health Statistics (NCHS) – Centers for Disease Control and Prevention.

^†Note: Responses “Refused,” “Not ascertained,” “Don’t know” to all the factors questions were recoded as missing.

^††The Federal poverty level was derived from the ratio of family income to the poverty threshold.

^§Chosen as reference category in regression analysis.