Table 3. Univariate associations with variables in 304 clusters of 13,543 individuals aged ≥ 40 years in Nigeria, 2005–2007.

Variables		Group	OR (p-value)
Field-collected variables	Individual level
	Age group:	40–49 years	1
		50–59 years	1.68 (0.02)
		60–69 years	4.00 (<0.0001)
		70–70 years	4.65 (<0.0001)
		80+ years	5.30 (<0.0001)
	Gender	Female	2.61 (<0.0001)
	Literacy	Easily	1
		Difficult	4.11 (<0.0001)
		Not at all	2.06 (0.03)
	Improved water source	Unimproved	1
		Improved	1.40 (0.421)
	Proximate water source	Village or further	1
		Within street or household	0.95 (0.86)
	Occupation	Professional	1
		Semi Skilled	11.44 (0.03)
		Unemployed	35.55 (0.002)
	Cluster level
Climatic covariates	Mean annual precipitation (mm)		0.997 (<0.0001)
	Monthly Average land surface temperature (LST)		1.358 (<0.0001)
	Mean annual temperature (°C)		1.01 (0.59)
Environmental covariates	Altitude (meters)	<200	1
		200–499	14.41 (<0.0001)
		500 +	5.64 (<0.0001)
	Enhanced vegetation index (EVI)	≥ 0.35	1
		0.25–0.34	6.66 (0.001)
		0.15–0.24	26.00 (<0.0001)
		< 0.15	4.53 (0.01)
	Land cover type	Other	1
		Savannah/Grasslands	2.70 (<0.0001)
	Urban classification	Rural	1
		Urban	0.27 (<0.0001)
	Distance to surface water (km)		1.18 (<0.0001)
	Population density (per 5km cell)		0.99 (<0.0001)
	Ruminant density (per 5km cell)		1.003 (0.02)

All associations adjusted for clustering within villages