Table 3.

Association of Baseline Serum Sodium with Increase in Blood Pressure Stage and the Development of Hypertension on Follow-up.

Serum Sodium	Increase in Blood Pressure Stage*		Hypertension†
	Adjusted Odds Ratio (95% CI)	p value	Adjusted Odds Ratio (95% CI)	p value
A. Continuous variable
1 SD increase	0.93 (0.85,1.03)	0.159	0.94 (0.82,1.08)	0.389
B. Serum sodium categories
First (lowest)	1.19 (0.93,1.52)	0.156	1.15 (0.82,1.61)	0.411
Second	1.0	Referent	1.0	Referent
Third	1.0		1.0
Fourth (highest)	1.01 (0.81,1.26)	0.928	0.92 (0.67,1.26)	0.595

Odds ratios were adjusted for age, sex, baseline blood pressure category, systolic blood pressure, diastolic blood pressure, body-mass index, percentage weight gain, diabetes, and smoking status. CI denotes confidence interval.

^*An increase in blood pressure stage was defined as an increment of at least one blood pressure category (as defined by the sixth report of the Joint National committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure).

^†Hypertension was defined as a systolic blood pressure of 140mm Hg or higher, a diastolic blood pressure of 90mm Hg or higher, or the use of antihypertensive medications.