The use of predefined diet quality scores in the context of CVD risk during urbanization in the South African Prospective Urban and Rural Epidemiological (PURE) study

Abstract

Objective: Urbanization is generally associated with increased CVD risk and accompanying dietary changes. Little is known regarding the association between increased CVD risk and dietary changes using approaches such as diet quality. The relevance of predefined diet quality scores (DQS) in non-Western developing countries has not yet been established.

Design: The association between dietary intakes and CVD risk factors was investigated using two DQS, adapted to the black South African diet. Dietary intake data were collected using a quantitative FFQ. CVD risk was determined by analysing known CVD risk factors.

Setting: Urban and rural areas in North West Province, South Africa.

Subjects: Apparently healthy volunteers from the South African Prospective Urban and Rural Epidemiological (PURE) study population (n 1710).

Results: CVD risk factors were significantly increased in the urban participants, especially women. Urban men and women had significantly higher intakes of both macro- and micronutrients with macronutrient intakes well within the recommended CVD guidelines. While micronutrient intakes were generally higher in the urban groups than in the rural groups, intakes of selected micronutrients were low in both groups. Both DQS indicated improved diet quality in the urban groups and good agreement was shown between the scores, although they seemed to measure different aspects of diet quality.

Conclusions: The apparent paradox between improved diet quality and increased CVD risk in the urban groups can be explained when interpreting the cut-offs used in the scores against the absolute intakes of individual nutrients. Predefined DQS as well as current guidelines for CVD prevention should be interpreted with caution in non-Western developing countries.

Fig. 1

(colour online) Bland–Altman plots showing the agreement between two predefined diet quality scores (DQS; the Healthy Diet Indicator^{( 13 )} and the Adapted Thiele Score^{( 12 )}) in apparently healthy volunteers from the South African Prospective Urban and Rural Epidemiological (PURE) study population (n 1710): (a) rural group and (b) urban group