Table 1.

Study variables

Hospital registry (LMR) variables	Measurement/definition	Level of measurement	Range/categories/unit
Outcome variables
Hospital admission	Admitted at least once within 36 months follow-up	Dichotomous	Yes/no
Day admission	At least one planned admission during the day within 36 months follow-up	Dichotomous	Yes/no
Overnight admission	At least one overnight admission (planned or acute) within 36 months follow-up	Dichotomous	Yes/no
Acute overnight admission	At least one acute overnight admission within 36 months follow-up	Dichotomous	Yes/no

LASA variables	Measurement/definition	Level of measurement	Range/categories/unit
Demographic variables
Age		Continuous	65–88 years
Gender		Dichotomous	Female/male
Education in years	Categories: 9 levels of education attained, recoded into education in years	Continuous	5–18 years
Income	Net monthly income in Euros. Income level of the second wave onwards was corrected for inflation (on average 2.3% per year). Net monthly income of respondents living with a partner was multiplied by 0.7, to make their income comparable with that of one-person households.	Continuous	334–2270 Euros
Marital status	Categories: unmarried, married, divorced, widowed	Dichotomous	Married/not married
Urbanisation level	Data are provided by Statistics Netherlands. Categories: 5 ‘very highly (>2500)’; 4 ‘highly (1500–2500)’; 3 ‘somewhat (1000–1500)’; 2 ‘little (500–1000)’; 1 ‘not (<500)’	Continuous	1–5
Institutionalised	Categories: independent housing, residential home, nursing home—somatic, nursing home—psychogeriatric	Dichotomous	Institutionalised/living independently
Psychosocial factors
Network size	Number of network members identified by the respondent in 7 types of relationships	Continuous	0–67
Received instrumental support Received emotional support	Four questions were asked about the relationships with a maximum of 9 network members with whom contact was most frequent. Instrumental support received: how often during the previous year the respondent had received help with daily chores around the house, such as preparing meals, cleaning the house, transportation and small repairs. Emotional support received: how often during the previous year they had talked to their network member about personal experiences and feelings. Categories: never (1), rarely (2), sometimes (3) or often (4)	Continuous Continuous	0–36 0–36
Mastery	Pearlin Mastery scale27	Continuous	5–25
Social loneliness	5 items of the 11-item scale De Jong Gierveld29	Continuous	0–5
Emotional loneliness	6 items of the 11-item scale De Jong Gierveld29	Continuous	0–6
Lifestyle factors
Alcohol intake	Self-reported number of days per week respondents usually drank×the number of glasses each time	Continuous	0–77 glasses/week
Body mass index	Measured weight (in kilogram)/height (in metres) squared	Continuous	kg/m2
Smoking	Self-reported smoking status. If respondents had stopped more than 20 years ago, they were categorised as non-smokers, since studies have shown similar mortality risks for those who stopped more than 20 years ago, compared with non-smokers.30	Nominal	Non-smoker/former smoker/current smoker
Sports physical activity	Self-reported frequency×duration of sports activities. If the frequency or the time spent on the activity was missing, we imputed these by substituting with gender-specific and activity-specific means.	Continuous	min/day
Non-sports physical activity	Self-reported frequency×duration of non-sports activities. If the frequency or the time spent on the activity was missing, we imputed these by substituting with gender-specific and activity-specific means.	Continuous	min/day
Health factors
Chronic diseases	Self-reported presence of chronic non-specific lung disease, cardiac disease, peripheral arterial disease, stroke, diabetes mellitus, arthritis, cancer and a maximum of 2 other diseases that had been present for at least 3 months33	Continuous	0–9
Functional limitations	Self-reported number of activities out of 6 that respondents had difficulty performing34 35	Continuous	0–6
Self-rated health	Categories: very good (1), good (2), fair (3), sometimes good, sometimes bad (4), poor (5)36	Continuous	1–5
Contact with general practitioner	Self-reported contact with a general practitioner in the previous 6 months	Dichotomous	Yes/no
Contact with medical specialist	Self-reported contact with a medical specialist in the previous 6 months	Dichotomous	Yes/no
Physical performance	Time in seconds measured for 3 performance-based tests (walking speed, ability to rise from a chair and putting on and taking off a cardigan). Sum scores of test-specific quartiles ranged from 0 to 12, with 12 indicating the best performance.37	Continuous	0–12
Polypharmacy	The number of drugs used was recorded from the medicine containers in the home of the respondents. Polypharmacy was defined as having ≥5 vs <5 drugs prescribed.39 40	Dichotomous	≥5 vs <5
Systolic and diastolic BP	Measurements were performed in sitting position. If multiple BP measurements were available (waves 2001–2002 and 2005–2006), only the first measurement was used to make the measurements comparable across waves.	Continuous	mm Hg
Depressive symptoms	Center for Epidemiologic Studies Depression Scale41	Continuous	0–60
Cognitive functioning	Mini-Mental State Examination42	Continuous	0–30

BP, blood pressure; LASA, Longitudinal Aging Study Amsterdam; LMR, Landelijke Medische Registratie.