Incidence of hypertension in individuals with different blood pressure salt-sensitivity: results of a 15-year follow-up study.
OBJECTIVE
To evaluate the incidence of hypertension and the rate of decline in renal function in a sample of 47 Olivetti Heart Study (OHS) participants whose blood pressure (BP) salt-sensitivity and renal tubular sodium handling had been assessed in 1987-88.


METHODS
During the 2002-04 OHS follow-up examination, medical history, physical examination and blood and urine sampling were performed in 36 of the 47 participants to the baseline study (age 60 +/- 6 years; average follow-up = 15.1 +/- 0.6 years). The renal length was measured in 23 participants by kidney ultrasonography. Based on the baseline salt-sensitivity evaluation, the subjects were classified into a lower salt-sensitivity (LSS, n = 20) and a higher salt-sensitivity group (HSS, n = 16).


RESULTS
In comparison with the LSS group, HSS participants had a significantly higher incidence of hypertension (87.5 versus 50.0%, P = 0.02), a higher glomerular filtration rate (median, first to fourth quartile: 81.9, 72.3-95.2 versus 72.3, 59.9-81.2 ml/min; P = 0.03) and greater kidney length (median, first to fourth quartile: 68.2, 63.3-72.1 versus 61.9, 58.7-62.7 mm/m of height; P = 0.003). The incidence of hypertension remained significantly higher in HSS individuals after adjustment for age, intercurrent changes in body mass index and baseline blood pressure on low sodium diet (P = 0.04).


CONCLUSIONS
Our findings indicate that individuals with higher BP salt-sensitivity have a higher rate of incident hypertension and suggest an altered renal tubular sodium handling involving a trend to increased glomerular filtration rate and blood pressure over time as a possible mechanism.
Barba
Gianvincenzo
G
Epidemiology and Population Genetics, Institute of Food Sciences, CNR, Avellino, Italy. gbarba@isa.cnr.it
Galletti
Ferruccio
F
Cappuccio
Francesco P
FP
Siani
Alfonso
A
Venezia
Antonella
A
Versiero
Marco
M
Della Valle
Elisabetta
E
Sorrentino
Paolo
P
Tarantino
Giovanni
G
Farinaro
Eduardo
E
Strazzullo
Pasquale
P
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000139:chemically induced / Q000453:epidemiology* / Q000503:physiopathology; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D007668:Kidney / Q000000981:diagnostic imaging / Q000502:physiology; D008297:Male; D008875:Middle Aged; D017673:Sodium Chloride, Dietary / Q000009:adverse effects*; D014463:Ultrasonography
D017673:Sodium Chloride, Dietary