Blood pressure in subjects from rural Greece, comparing individuals migrating to Melbourne, Australia with non-migrant relatives.
The aim of the study was to compare the systolic and diastolic blood pressures in 525 individuals who had migrated from rural Greece to Melbourne, Australia with those in 367 nonmigrant relatives (all aged 30 to 59 years and still living in the source area), and to relate any differences to previously identified correlates of BP. This migrant family design offers enhanced environmental heterogeneity while controlling in large part for genetic and other familial factors. Migrating siblings differed from nonmigrating siblings on some variables determined at the time of migration but these were not independently associated with BP. Migrants had been in Australia for an interquartile range of 19 to 25 years. DBP was higher in migrants by 4.57 (+/- 0.97) mmHg for males and 2.66 (+/- 0.86) mmHg for females. SBP was not different at age 30 years but increased more steeply with age in the migrants: 0.89 (+/- 0.17) mmHg/yr vs. 0.41 (+/- 0.13) mmHg/yr in males and 1.18 (+/- 0.14) mmHg/yr compared with 0.83 (+/- 0.15) mmHg/yr in females. Significant associations, independent of age, were found only with body mass index and ambient temperature at the time and place of measurement. There was no consistent association with alcohol despite a wide range of exposures, with dietary and psychosocial variables, or with length of residence independent of age. The higher body mass index of and lower ambient temperatures for migrants accounted for differences in mean DBP but not in SBP. Proportions defined as hypertensive were similarly associated only with migrant status, body mass index and temperature. Pressures in Greece were substantially below predictions derived from the Intersalt data set, suggesting unidentified protective factors.
Powles
J W
JW
Department of Social and Preventive Medicine, Monash Medical School, Melbourne, Australia.
Hopper
J L
JL
Macaskill
G T
GT
Ktenas
D
D
D000328:Adult; D000375:Aging / Q000502:physiology; D001315:Australia / Q000208:ethnology; D001794:Blood Pressure; D005260:Female; D005544:Forecasting; D006115:Greece / Q000208:ethnology; D006801:Humans; D006973:Hypertension / Q000209:etiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011336:Probability; D012423:Rural Health; D012727:Sex Characteristics; D014171:Transients and Migrants