Rural and semi-urban differences in salt intake, and its dietary sources, in Ashanti, West Africa.

Objectives: To provide a socioeconomic profile of rural and semi-urban settings in Ashanti, West Africa and to investigate the relationship between urbanization and sources of salt in the diet.

Setting: 12 villages (6 rural, 6 semi-urban) participating in a cluster randomized controlled trial of a health promotion in the Ashanti region of Ghana.

Participants: 1013 adult men (N = 385) and women (N = 628), aged 40-75.

Method: Between June 2001 and June 2002, participants completed a detailed questionnaire on demography, occupation and education, housing, radio and television use, personal and family medical history, drug therapy, smoking, alcohol consumption, and diet.

Results: 532 subjects lived in semi-urban and 481 in rural communities. Ninety-two percent of the participants were of the Ashanti tribe and 94% spoke Twi. The semi-urban villages were closer to Kumasi, the second largest city in Ghana, had larger population (1727 vs 1100 people) and household sizes (14.6 vs 8.8 persons per household; P < .001), had fewer farmers (53% vs 81%; P < .001) and more traders (22% vs 7%; P < .001), and had more homes with electricity (81% vs 17%; P < .001) and piped water (28% vs 0.2%; P < .05). Semi-urban villagers had higher systolic blood pressure than rural villagers (129 vs 121 mm Hg difference 8 mm Hg [95% CI 5-11]; P < .001). Salt is almost invariably added to food in cooking (98%), and salted foods such as fish and meat are eaten in both communities. Salt is often added at the table (52%), more often in rural villages than in semi-urban settings (59% vs 45%; P < .01), although the total salt consumed as measured by urinary sodium was similar (99 vs 103 mmol/day). Potassium levels were higher in rural villages (58 vs 40 mmol/day difference 18 mmol/day [95% CI 11-26]; P < .001).

Conclusions: In this mainly farming community were clear differences in housing, population structure, and blood pressure between rural and semi-urban communities. While no significant differences were in the amount of salt consumed, the sources of salt differed between rural and semi-urban settings. Finally, rural villagers ate more potassium than semi-urban participants.