Table 1:

Characteristics of study areas and samples

Country	Study type	Rationale	Area name	Urban %a	Climate	Survey dates	Survey season	Source Population	Overall response rate %	Sample informationb
										n	Male %	age, years median (IQR)
Chile	Reuse of population survey37	Proposed risk factors	Molina	69	Mediterranean	Oct22–Nov23	All year	45 976	92	476	41	53 (48, 57)
Ecuador	CKD focused study38	DEGREE registered	Miguelillo, Manabi Province	0	Tropical	Jul21–Sep21	Dry	14 164	61	754	41	39 (28, 49)
England	HSE 2016 – Reuse of population survey21	Reference	England	83	Temperate	2016	All year	56 000 000	59	2135	42	44 (34, 52)
Guatemala	CKD focused study39	DEGREE registered	Tecpán, Chimaltenango	0	Temperate Highland Tropical	Jun18–Oct19	All year	85 000	58	336	34	34 (24, 47)
			San Antonio Suchitepequez	0	Tropical Wet	Jun18–Oct19	All year	52 000	69	318	34	33 (25, 45)
India	1. CARRS - Reuse of population survey40	DEGREE registered	Chennai	100	Tropical	Oct10–Nov11	All year	4 680 000	92	5 366	43	39 (31, 47)
			Delhi	100	Semi-arid	Oct10–Nov11	All year	16 300 000	96	3 564	49	42 (35, 50)
	2. ICMR-CHD – Reuse of population survey41	DEGREE registered	Delhi	100	Semi-arid	Aug11–Jan12	Rainy, autumn, winter	16 300 000	Not reported	1888	44	41 (35, 48)
			Faridabad	0	Semi-arid	Aug11–Jan12	Rainy, autumn, winter	90 000	Not reported	1413	45	42 (36, 49)
	3. UDAY - Reuse of population survey42	DEGREE registered	Sonipat	50	Semi-arid	Jul14–Dec14	Rainy, autumn, winter	203 000	90c	4126	44	44 (37, 51)
			Vizag	50	Tropical	Jul14–Dec14	Rainy, autumn, winter	275 000		4 209	44	43 (35, 50)
	4. Uddanam - CKD focused study43	Reported high CKDu area	Kanchili	0	Hot Tropical	Jun18– Dec19	Summer, winter	66 657	85c	317	47	43 (35, 51)
			Kaviti	0	Hot Tropical	Jun18–Dec19	Summer, winter	75 974		212	48	43 (35, 51)
			Mandasa	0	Hot Tropical	Jun18–Dec19	Summer, winter	82 699		200	48	42 (33, 50)
			Palasa	0	Hot Tropical	Jun18–Dec19	Summer, winter	97 551		362	51	44 (36, 51)
			Sompeta	0	Hot Tropical	Jun18–Dec19	Summer, winter	78 908		443	46	42 (33, 51)
			V_kothuru	0	Hot Tropical	Jun18–Dec19	Summer, winter	73 212		531	47	44 (35, 52)
	5. Prakasam – CKD focused studyd	DEGREE registered	Kanigiri	0	Hot Tropical	Dec21–Feb22	Winter	1780	84	1052	40	39 (30, 49)
Italy	CKD focused study44	Reported high CKD area	Barga	0	Temperate	Jun21–Mar22	Summer, autumn, winter	9 574	92e (or 50f)	301	43	47 (33, 54)
Kenya	CKD focused study45	DEGREE registered	Muhoroni East	100	Sub-tropical	Jul20–Nov20	Dry	3 740	85	260	53	34 (26, 43)
			Owaga	0	Sub-tropical	Jul20–Nov20	Dry	3 769	87	242	47	36 (26, 46)
			Tonde	0	Sub-tropical	Jul20–Nov20	Dry	3 045	98	233	49	36 (28, 45)
Malawi	CKD focused study46	DEGREE registered	Southern Karonga District	0	Sub-tropical	Jan18–Aug18	Dry, rainy	40 000	66	646	42	33 (24, 41)
			Lilongwe	100	Sub-tropical	Jan18–Aug18	Dry, rainy	66 000	37	312	31	28 (22, 38)
Nepal	Reuse of population survey47	Proposed risk factors	Nepal	67	Sub-tropical to Arctic	2016–2018	All year	29 000 000	92	8 916	37	41 (33, 50)
Nicaragua	1. CKD focused study3	Reported high CKDu area	Chinandega (banana/sugarcane)	0	Tropical	Jul07–0ct07	Rainy	384	86	331	47	34 (26, 44)
			Chinandega (service)	0	Tropical	Jul07–0ct07	Rainy	177	79	140	36	32 (25, 43)
			Leon (coffee)	0	Tropical	Jul07–Oct07	Rainy	92	84	77	52	36 (27, 46)
			Leon (fishing)	0	Tropical	Jul07–Oct07	Rainy	216	77	166	46	32 (25, 44)
			Leon (mining)	0	Tropical	Jul07–Oct07	Rainy	445	86	382	41	33 (26, 43)
	2. CKD focused study48	Reported high CKDu area	Leon municipality	70	Tropical	Jun14–Sep14	Rainy	204 000	97	1672	39	37 (28, 48)
Peru	CKD focused study49	DEGREE registered	Tumbes	94	Arid and Sub-tropical	Nov17–May18	Spring, summer, autumn	224 863	83	1238	43	39 (30, 49)
Sri Lanka	Anuradhapura District - CKD focused study6	DEGREE registered	Halambagaswewa, Rambewa	0	Tropical	Mar17–May17	Dry	1 188	90	739	33	41 (33, 49)
			Lolugaswewa, Medawachchiya	0	Tropical	Mar17–May17	Dry	1 262	86	790	28	41 (34, 50)
			Pothana, Mihintale	0	Tropical	Mar17–May17	Dry	1391	88	691	28	41 (33, 51)
			Puhudivula, Medawachchiya	0	Tropical	Mar17–May17	Dry	1362	91	798	28	41 (32, 50)
			Sangilikandarawa, Rambewa	0	Tropical	Mar17–May17	Dry	1 228	90	818	33	41 (33, 50)
Thailand	Reuse of population survey50	Proposed risk factors	Bangkok	100	Tropical	Nov13–Aug14	Cool, hot, rainy	6 969 010g	81	1604	24	48 (40, 55)
			Central	46	Tropical	Nov13–Aug14	Cool, hot, rainy	14 424 785g	92	2 752	41	46 (35, 54)
			North	35	Tropical	Nov13–Aug14	Cool, hot, rainy	8 638 732g	83	2 447	45	47 (37, 54)
			North East	29	Tropical	Nov13–Aug14	Cool, hot, rainy	13 445 305g	80	2 315	46	46 (36, 53)
			South	34	Tropical	Nov13–Aug14	Cool, hot, rainy	6 442 937g	73	2 019	42	44 (34, 53)
USA	NHANES 2017–8 – Reuse of population survey22	Reference	USA	83	All types	2017–2018	All year	320 842 721	49	3373	47	39 (30, 49)

^aProportion of the source population of the area living in an urban environment

^bincludes ages 18–60 with complete data available;

^coverall response rate not area-specific;

^dpersonal communication Professor Prabhdeep Kaur (kprabhdeep@gmail.com);

^edenominator includes refusal/incomplete surveys but excludes mailing failures;

^fdenominator includes mailing failures;

^gpopulation over age 20;

HSE=Health Survey England; CARRS=Centre for cArdiometabolic Risk Reduction in South-Asia; ICMR-IHD=Indian Council of Medical Research International Health Division; UDAY=means dawn in Sanskrit; NHANES=National Health and Nutrition Examination Survey;