TABLE 2.

Regression coefficients (95% CIs) and P values in the association between explanatory variables and UIC¹

Characteristics	Coefficients (β)	95% CI	P
Age (y)	−0.0004	−0.0016, 0.0001	0.25
Pregnancy status
Pregnant	−1.21	−3.42, −0.12	0.004
Not pregnant	Reference
Breastfeeding status
Breastfeeding	−1.02	−2.25, −0.27	<0.0001
Not breastfeeding	Reference
Iodine content in salt
Inadequately iodized salt (<15 ppm)	−6.55	−9.24, −4.33	<0.0001
Adequately iodized salt (≥15 ppm)	Reference
Educational status
No education	−1.88	−4.58, −0.36	0.0005
Primary education	−0.45	−1.54, −0.01	0.02
Secondary/higher	Reference
Wealth index status
Lowest	−1.61	−3.61, −0.41	<0.0001
Middle	−1.72	−3.88, −0.44	<0.0001
Highest	Reference
Place of residence
Rural	−0.42	−1.42, −0.01	0.02
Urban	Reference
Employment status
Employed	−0.20	−0.96, 0.01	0.09
Unemployed	Reference
Geographic zone
Central	−9.61	−16.81, −4.37	<0.0001
Lake	−19.98	−27.77, −13.40	<0.0001
Northern	−7.13	−12.89, −3.06	<0.0001
Southern	−12.11	−24.11, −4.24	<0.0001
Southern Highlands	−23.43	−31.81, −16.24	<0.0001
Western	−26.63	−37.70, −17.39	<0.0001
Zanzibar	−11.02	−17.98, −5.71	<0.0001
Eastern	Reference

¹Model fully adjusted for age, pregnancy status, breastfeeding status, educational status, wealth index status, iodine content in salt, place of residence, employment status, and geographic zone. ppm, parts per million; UIC, urinary iodine concentration.