Table 1 Overview and assessment of the outcome battery
Outcome | Type of measurement | Response scale |
|---|---|---|
I) Pathologies | ||
1. Non-communicable disease (NCD) morbidity | Self-reported physician diagnosis1 of any one condition listed #2-#7; “Has a doctor ever told you that you had […]?” | 0 = yes; 1 = no |
2. Asthma | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
3. Other chronic lung diseases | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
4. Cancer or malignant tumours | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
5. Diabetes or high blood sugar | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
6. Cardiovascular diseases (heart attacks, coronary heart diseases, angina, or other heart problems) | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
7. Stroke | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
8. Prediabetes or diabetes based on glycosylated haemoglobin (HbA1c) levels2 | Biomarker; Dried blood spots (DBS) based assays taken from trained IFLS interviewers to measure glucose metabolism. | Continuous variable (range: 3.5–12.8%); Binary variable: 0 = yes (diabetes or prediabetes, > 5.7%); 1 = no (normal range < 5.7%)3 |
II) Impairments | ||
Cardiovascular impairments: 9. Hypertension | Three measures of systolic and diastolic blood pressure (BP) in mmHg on alternate arms (starting left) by trained IFLS interviewers using an Omron meter (HEM-7203) and self-reported use of antihypertensive medication. | 0 = yes (hypertensive; defined as mean systolic BP ≥140 mmHg and/or mean DBP ≥90 mmHg and/or current use of antihypertensive medication); 1 = no (normotensive)4 |
Immunological impairments: 10. Chronic inflammation based on C-reactive protein (CRP) levels2 | Biomarker; CRP (plasma equivalent) concentrations from finger-prick DBS specimens measured using validated enzyme-linked immunosorbent assay (ELISA) method. | Continuous variable (range: 0.01–58.95 mg/l); Binary variable: 0 = yes (> 1.0 mg/l); 1 = no (normal range < 1.0 mg/l)5 |
Muscoskeletal impairments: 11. Mean hand grip strengths | Physical performance test; Hand grip strengths was measured by a trained IFLS interviewer using a Baseline Smedley Spring type dynamometer (daily calibration). Respondents were asked to squeeze the dynamometer in each hand twice beginning with the dominant hand. Two measurements per hand were recorded including information on any recent surgery, swelling, inflammation, severe pain, or injury on one or both hands and recording of dominant hand. | Continuous variable (mean of four measurements, range: 0–47.75 kg) |
12. Arthritis and/or rheumatism | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
Sensory impairments: 13. Hearing and/or vision problems | Self-reported physician diagnosis1 | 0 = yes; 1 = no |
III) Functional limitations | ||
Physical functional limitations 14. Upper-body functional limitations (UBFL)6 | Self-reported physical functioning measures; including show cards; Question: “If you had […], could you do it?” 1) to carry a heavy load (like a pail of water) for 20 m 2) to draw a pail of water from a well 3) to sweep the house / floor / yard | 0 = yes (includes responses “with difficulty” and “unable to do it”); 1 = no (“easily”) |
15. Lower-body functional limitations (LBFL)7 | Self-reported physical functioning measures; including show cards; Question: “If you had […], could you do it?” 1) to walk 1 km 2) to bow, squat, or kneel 3) to stand up from sitting on the floor without help | 0 = yes (includes responses “with difficulty” and “unable to do it”); 1 = no (“easily”) |
Cognitive functional limitations 16. Episodic memory score | Cognitive performance test; Immediate and delayed word recall of ten nouns. These were read out slowly and the respondent was asked to repeat the list immediately and again after 4 to 5 min. Questionnaire contained four lists of each ten words which were randomized across individuals within a household. | Continuous variable (mean number of words correctly recalled for both immediate and delayed response; range: 0–8.5 words) |
17. Visuospatial ability score | Cognitive performance test; IFLS uses an abridged version of the Raven’s Progressive Matrices8, a non-verbal self-paced test in which each item contained a pattern with a missing part. The respondent had to infer the rules underlying the pattern and apply these rules to discover which of the answer options provides the correct completion for a total of eight items. | Continuous variable (one score point per correct answer; range: 0–8 points) |
IV) Disabilities | ||
18. Activities of daily living (ADLs) limitations9 | Self-reported physical functioning measures for five basic tasks of everyday life; including show cards; Question: “If you had […], could you do it?” (1) to dress without help (2) to bathe (3) to get out of bed (4) to eat (eating food by oneself when it is ready) (5) to control urination or defecation | Continuous variable (range 5–25); Binary variable: 0 = yes (includes responses “with difficulty”, “can do with help” and “unable to do it”); 1 = no (“easily”) |
19. Instrumental activities of daily living (IADLs) limitations10 | Self-reported ability to perform IADLs items; including show cards); Question: “If you had […], could you do it?” (1) to shop for personal needs (2) to prepare hot meals (prepare ingredients, cooking, and serving food) (3) to take medicine (right portion at right time) (4) to do household chores (house cleaning, doing dishes, making the bed, and arranging the house) (5) to shop for groceries (deciding what to buy and pay for it) (6) to manage your money (paying your bills, keeping track of expenses, or managing assets) | Continuous variable (range 6–30); Binary variable: 0 = yes (includes responses “with difficulty”, “can do with help” and “unable to do it”); 1 = no (“easily”) |