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Table 1 Definition of Covariates

From: The impact of residential status on cognitive decline among older adults in China: Results from a longitudinal study

Variable name Data collection
time points
Definitions
Demographic characteristics
 Age 2002–2014 Continuous variable
 Gender 2002 Male = 1, female = 0
 Ethnicity 2002 Han = 1, non-Han minorities = 0
Socioeconomic Factors
 Education 2002 No education = 0, received 1–6 years schooling = 1, received 7 years or more education = 2
 Prof./admin. Occupation 2002 Professional work = 1, others = 0
 Economic independence 2002 A dichotomized variable with 1 if the respondent’s primary financial source was from own work or pension, 0 if not
 Childhood SES 2002 a continuous variable ranging from 0 to 4 with 1 point each if the respondent was obtained \adequate medical services, or went to bed without hunger, or if both parents were alive at age 10, or the father’s occupation was white collar
Family Support Factors
 Marital status 2002–2014 Married = 1, others = 0
 High proximity to children 2002–2014 A dichotomized variable with 1 if the respondent was co-residing with children or had at least 1 biological children living in the same village or street block
Behavioral Factors
 Current smoking 2002–2014 Yes = 1, no = 0
 Exercises regularly 2002–2014 Yes = 1, no = 0
 Consuming vegetables 2002–2014 A dichotomized variable with 1 if the respondents said that they consumed vegetables “almost every day”, 0 if answered “occasionally” or “rarely or never.”
 Consuming fish 2002–2014 A dichotomized variable with 1 if the respondents said that they consumed fish “almost every day”, 0 if answered “occasionally” or “rarely or never.”
Health Status
 Any chronic condition 2002–2014 A dichotomized variable with 1 if the respondents said that they reported hypertension, a pulmonary disorder, heart attack, or cerebrovascular disease.
 Any ADL disability 2002–2014 A dichotomized variable with 1 if the respondents said that they needed any help in performing the following tasks: bathing, dressing, toileting, indoor transferring, maintaining continence, and eating.
 Any IADL disability 2002–2014 A dichotomized variable with 1 if the respondents said that they needed any help in performing the following tasks: visiting neighbors, washing clothes, walking one kilometer, shopping, cooking, lifting 5 kg, crouching and standing up three times, and using public transportation
 Attrition 2002–2014 Survivor = 0, loss to follow-up = 1, deceased = 2
  1. Note: all covariates are time varying with the exception of participants’ demographic and socioeconomic factors.