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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.