Measurement of physical activity in urban and rural South African adults: a comparison of two self-report methods

Background Due to the large mortality from inactivity-related non-communicable diseases in low- and middle- income countries, accurate assessment of physical activity is important for surveillance, monitoring and understanding of physical (in)activity epidemiology in many of these countries. Research on relative performance of self-report physical activity instruments commonly used for epidemiological research in Africa have rarely been reported. The present study compared estimates of physical activity measured with the International Physical Activity Questionnaire – Short Form (IPAQ-SF) and the Baecke Physical Activity Questionnaire (BPAQ) among urban and rural black South African adults. Methods Self-reported physical activity data using the IPAQ-SF and BPAQ were collected from a representative sample of 910 urban and rural black South African adults (age = 59.2 ± 9.5 years, 69.7 % women) participating in the 2015 wave of the Prospective Urban and Rural Epidemiological (PURE) study in the North West Province of South Africa. Between-method relationships (pearson correlations [ r ] and intraclass correlation coefficients [ICCs]) and agreements (Bland-Altman mean difference with 95 % limits of agreement and Kappa coefficient [ k ]) of IPAQ-SF and BPAQ variables were estimated. Sensitivity and specificity of the BPAQ relative to the IPAQ-SF to classify individuals according to the international guidelines for sufficient physical activity were calculated using chi-square statistics. Results Correlations between IPAQ-SF scores and BPAQ indices were small ( r = 0.08–0.18; ICCs = 0.09–0.18) for BPAQ leisure and sport indices, moderate-to-large for work index ( r = 0.42–0.59; ICCs = 0.40–0.62) and total physical activity index ( r = 0.52–0.60; ICCs = 0.36–0.51). Between methods mean difference for total physical activity was large (1.85 unit), and agreement in physical activity classifications was poor to moderate (k = 0.16–0.44). The sensitivity of the BPAQ to identify sufficiently active people from the ...