Tuberculosis and tubulointerstitial nephritis: an intriguing puzzle.

Classical renal tuberculosis is a well-known cause of urinary tract scarring and calcification, and sometimes renal dysfunction. In the past two decades there have been reports, particularly from the United Kingdom among immigrants from the Indian subcontinent, of a more insidiously progressive form of renal disease. Ultrasound shows small smooth kidneys, and histology reveals tubulointerstitial nephritis including granulomas but not acid-fast bacilli. Evidence is mounting that the underlying cause may be tuberculosis, but the mechanism remains obscure.

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.