PURPOSE: Immigration from a Third-World society to a Western society can be associated with higher blood pressure and salt sensitivity. We therefore tested whether immigrants from Afghanistan to Denmark compared with non-immigrant Danes exhibit a (i) higher 24-h ambulatory blood pressure (24-h ABP) and (ii) blunted renin response to a change in salt intake.

METHODS: Twenty-four-hour ABP was measured in 40 men of Afghan (Afghans) and 40 men of Danish (Danes) origin. Each group was divided into young (20-30 years, n = 20) and middle aged (40-60 years, n = 20). A 3-day low (70 mmol per 24-h) and a 3-day high (250 mmol per 24-h) salt intake were in addition instituted in subgroups of the young groups (n = 18).

RESULTS: Young and middle-aged Afghans exhibited a lower 24-h mean arterial pressure (24-h MAP) than the same respective age groups of Danes (83 ± 1 versus 90 ± 1 mm Hg, P<0·05, and 89 ± 2 versus 100 ± 1 mm Hg, P<0·05). 24-h ABP did not change in any of the young groups during increased salt intake, whereas the Danes exhibited a greater decrease in plasma renin activity (PRA) (P<0·05). Plasma noradrenaline (PNA ) was significantly higher among the young Afghans.

CONCLUSIONS: Afghan immigrants to Denmark exhibit a lower 24-h ABP than Danes. In young Afghans, PRA is less sensitive to changes in salt intake, while PNA is higher and may reflect their lower systolic blood pressure and/or arterial pulse pressure. Whether these hormonal differences can explain the lower 24-h ABP in Afghans should be further explored.