Table 2.

Salt intake (g/d) as assessed by 24-h urinary sodium excretion among participants aged 4–12 years at baseline (n 666) and follow-up (n 161), stratified by sex, age group, parental educational attainment and socio-economic disadvantage of school

Demographic group	Baseline			Follow-up			Unadjusted			Adjusted*			P-value for interaction between demographic characteristic and time point
	n	Mean	95 % CI	n	Mean	95 % CI	Mean difference	T2, T1	P-value	Mean difference	T2, T1	P-value
Sex
Boys	365	6·4	6·0, 6·7	84	6·8	5·8, 7·7	0·4	−0·5, 1·3	0·39	0·1	−0·7, 0·9	0·79†	0·04
Girls	301	5·7	5·4, 6·0	77	5·5	4·6, 6·3	−0·2	−0·9, 0·6	0·65	−0·6	−1·1, -0·2	0·004 †
Age group
4–8 years	283	5·3	5·0, 5·5	48	5·1	4·0, 6·3	−0·2	−1·2, 0·9	0·80	−0·1	−0·8, 0·4	0·55‡	0·64
9–12 years	383	6·6	6·3, 6·9	113	6·6	5·7, 7·4	−0·0	−0·9, 0·8	0·91	−0·3	−1·1, 0·4	0·41†
Parental educational attainment
Low	137	6·4	6·0, 6·9	18	5·4	4·2, 6·6	−1·0	−2·2, 0·2	0·09	−1·4	−2·5, -0·3	0·02 §	0·02
Mid	85	5·8	5·4, 6·3	26	6·1	4·6, 7·5	0·2	−1·2, 1·7	0·75	0·5	−0·7, 1·7	0·38§
High	348	5·8	5·5, 6·1	99	6·5	5·5, 7·3	0·6	−0·4, 1·5	0·22	0·1	−0·6, 0·8	0·73§
Socio-economic disadvantage of school
Low (most disadvantaged)	108	6·3	5·9, 6·7	51	6·5	5·3, 7·7	0·2	−1·3, 1·7	0·76	−0·9	−2·0, 0·2	0·10§	0·57
Mid	148	5·6	5·1, 6·2	62	6·3	4·9, 7·7	0·7	−1·2, 2·6	0·44	0·11	−1·2, 1·4	0·85§
High (least disadvantaged)	410	6·1	5·8, 6·4	48	5·6	4·7, 6·6	−0·5	−1·4, 0·4	0·26	−0·4	−0·9, 0·1	0·08§

^*All regression models adjust for clustering of participants within schools.

^†Linear regression with adjustment for age, BMI Z-score, day of urine collection and socio-economic disadvantage of school.

^‡Linear regression with adjustment for sex, BMI Z-score, day of urine collection and socio-economic disadvantage of school.

^§Linear regression with adjustment for age, sex, BMI Z-score and day of urine collection.

P-values <0·05 bolded.