Lung function, inflammation and cardiovascular mortality in Africans.
BACKGROUND
The link between impaired lung function and cardiovascular outcome is well established in European and American populations. It is possible that this association may be driven by a systemic spillover of inflammation occurring within the lungs. As several studies have found an increased level of inflammatory markers in African populations, we aimed to establish the contribution of lung function in predicting all-cause and cardiovascular mortality in Africans, whilst taking inflammatory markers into account.


METHODS
We followed 1442 black South Africans from the North West Province participating in the South African leg of the Prospective Urban and Rural Epidemiology (PURE) study, over a five-year period. Spirometry, cardiovascular and metabolic measures were performed, and cardiovascular mortality as well as all-cause mortality used as endpoints.


RESULTS
In univariate Cox regression models, both forced expiratory volume in 1-s (FEV1) and forced vital capacity (FVC) predicted all-cause (P = 0·022; P < 0·001) and cardiovascular mortality (P = 0·004; P < 0·001). In multivariate adjusted standardized Cox regression analyses, only FVC predicted cardiovascular mortality independent of several covariates (hazard ratio, 0·57 [0·35-0·94]), including C-reactive protein (CRP). When CRP was replaced by interleukin-6 in the model, the significance of FVC was lost (hazard ratio, 0·85 [0·55-1·30]).


CONCLUSIONS
FVC, but not FEV1, is a strong predictor of both all-cause and CV mortality in black South Africans, which may be mediated by inflammation.
Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.
Yolandi
Y
Breet
Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.|MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
Aletta E
AE
Schutte
Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa.|MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
Hugo W
HW
Huisman
Occupational Hygiene and Health Research Initiative (OHHRI), North-West University, Potchefstroom, South Africa.
Fritz C
FC
Eloff
Occupational Hygiene and Health Research Initiative (OHHRI), North-West University, Potchefstroom, South Africa.
Johan L
JL
Du Plessis
MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.|Africa Unit for Transdisciplinary Health Research (AUTHeR), North-West University, Potchefstroom, South Africa.
Annamarie
A
Kruger
Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa. johannes.vanrooyen@nwu.ac.za.
Johannes M
JM
Van Rooyen
D000328:Adult; D000368:Aged; D044383:Black People / Q000208:ethnology; D002318:Cardiovascular Diseases / Q000208:ethnology* / Q000401:mortality / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000208:ethnology* / Q000401:mortality / Q000503:physiopathology; D011446:Prospective Studies; D012423:Rural Health / Q000706:statistics & numerical data; D013019:South Africa / Q000453:epidemiology / Q000208:ethnology; D014504:Urban Health / Q000706:statistics & numerical data; D014797:Vital Capacity / Q000502:physiology
African; South Africa; death; pulmonary function