Village distance from urban centre as the prime modernization variable in differences in blood pressure and body mass index of adults of the Purari delta of the Gulf Province, Papua New Guinea

Abstract

Objective: The study examined the extent to which the geographical proximity of villages to an urban centre and other modernization variables are associated with variation in blood pressure and body mass index (BMI) of adults of the Purari delta of the Gulf Province, Papua New Guinea (PNG).Methods: Mean BMI, systolic blood pressure (SBP) and diastolic blood pressure (DBP) of 292 adults surveyed in 1995–1997 in the Purari delta, PNG, are reported by village of residence, and related to modernization variables, including village of residence, urban life, urban connectedness, economic status and education.Results: Mean BMI, SBP and DBP differ according to village of residence, there being a gradient in mean blood pressure from highest in the village closest to the urban centre, Baimuru, and lowest in the village most distant from it. The gradients in these variables across the three villages are not due to differences in age structures between the villages. Place of residence, which represents the distance from town, has the greatest impact on the BMI of males, while among the females, the number of relatives living in urban centres had a significant effect on BMI. For both males and females, place of residence has the strongest effect on SBP. While for the males, place of residence is the only significant factor associated with SBP, for the females, SBP is also associated with BMI, level of income and to a lesser extent with age. Very similar results were obtained for DBP.Conclusions: Distance to urban centre appears to have a strong effect, relative to other modernization variables, on BMI and blood pressure, this effect being far stronger for males than for females. In large part, this effect operates by way of differences in number of sources of income as well as number of close relatives of women who are resident in an urban centre. Reasons for the male–female differences observed may include gender differences in degree of mobility, and possibly greater physical sensitivity of males to the environment than females. Traditionally, there have been clear divisions of labour between males and females, the latter spending longer in subsistence activities than the former. It is speculated that males have more free time to travel to town should they wish, while women may travel to town to take produce to market, and be limited by how much time they spend in town when they are there, by the need to return to carry out household and subsistence tasks. It may also be that young adult males are more susceptible to modernization, in that they exhibit a greater degree of non-conformity than young women, and may be more favourably disposed to adopt aspects of western lifestyle.