Prevalence and correlates of leisure-time physical activity among Nigerians

Worldwide, the contribution of different risk factors for disease burden has changed substantially, leading to a shift away from factors associated with high prevalence of communicable diseases which were particularly prevalent in children, towards those for non-communicable diseases that predominate in adulthood [1]. One of these risk factors is physical inactivity which is now the fourth leading risk factor for global morbidity and mortality. Physical inactivity was estimated to be associated with 21 to 25% of breast and colon cancer burden, 27% of diabetes and about 30% of ischemic heart disease burden in 2004 [2]. In 2010, physical inactivity and low physical activity accounted for 3 · 2 million (2 · 7 million to 3 · 7 million) deaths, and 2 · 8% (2 · 4 to 3 · 2%) of Disability-Adjusted Life Years (DALYs) globally [1]. Worldwide, 31% of adults are estimated to be physically inactive and these levels are rising with major public health implications [3]. The WHO recommends adults aged 18 to 64 years should do at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity activity weekly, in order to improve cardiorespiratory and muscular fitness, bone health and reduce the risk of NCDs and depression [4].

It is difficult to estimate trends in physical inactivity in sub-Saharan Africa due to the dearth of data. In a recent systematic review of the prevalence of physical activity in Ghana and Nigeria, 25 to 57% of Nigerians were estimated to be physically inactive though data from the various studies were considered to be limited, poorly reported and not easily comparable [5‐9]. Another recent study reported that 68.6% of Nigerian adults living in a metropolitan city in Northern Nigeria were sufficiently active [10]. This wide variation of physical activity prevalence may be due to different socio-demographic characteristics and lifestyle among the groups studied, as well as differences in the definition of physical inactivity and the tools used to measure physical activity.

Objective methods of measuring physical activity, such as accelerometry and heart rate monitoring are considered to be more accurate than self-report methods [11], but as the use of these methods are not feasible in large epidemiology studies involving thousands of participants, physical activity is usually measured by self-reports with questionnaires. A summary of the reliability and criterion validity results for 7 self-report physical activity measures evaluated in adults, reported reliability correlations ranging from 0.34 to 0.89, and criterion validity correlations of 0.14 to 0.53 [12]. The International Physical Activity Questionnaire Short Form (IPAQ-SF), which has been translated to over 20 languages [13], has been used for cross-national assessment of physical activity. A study carried out in 12 countries to determine the reliability and validity of the IPAQ-SF, showed that it had an agreement of about 80% and a correlation coefficient of 0.61 [14]. However, other investigators showed that in this study, the IPAQ-SF overestimated the prevalence of physical inactivity by 50% [15]. In addition, a systematic review showed that the IPAQ-SF typically overestimated physical activity as measured by objective criterion, by an average of 84% [16]. Nevertheless, the IPAQ is still being widely used to measure physical activity variation globally [17‐21].

A study to evaluate the reliability and validity of 5 commonly used physical activity questionnaires, showed that the Nurses’ Health Study (NHS) II physical activity questionnaire had statistically significant moderate reproducibility, correlation with average daily pedometer steps, total accelerometer counts per day and cardiovascular fitness [22]. To examine the prevalence and correlates of leisure-time physical activity in Nigeria, we conducted a cross-sectional survey in Abuja, Nigeria’s capital city using the NHS II physical activity questionnaire.

The mean age (SD) of the participants was 41.6 (9.3) years; 40% (416/1041) were women and 60% (625/1041) were men. Majority of the study population were Christians, married, completed university education and had professional jobs. The mean (SD) MET hours/week (h/wk) for all the participants was 6.8 (7.2) and it was not significantly different for women 6.5 (6.9) compared to men 6.9 (7.4), p-value = 0.12. The mean (SD) MET h/wk were 0.9 (0.7), 5.2 (1.7) and 11.5 (6.7) among those in the lowest, middle and highest tertiles of physical activity respectively, p-value = <0.001. The mean (SD) BMI of all the participants was 26.8 (7.2); it was significantly different for women, 29 (5.4), compared to men 26 (4.6), p-value = <0.001. Most women (74%) and men (56%) in this study were either overweight or obese. The mean (SD) BMI of the participants in the lowest tertile of physical activity was 27.4 (4.8), 27.3 (5.0) for those in the middle tertile and 26.7 (4.6) for those in the highest tertile of physical activity p-value = 0.62, suggesting that physical activity was not a major correlate of BMI in this population. Table 1 shows the characteristics of this population overall and by tertiles of MET h/wk.Few of the participants (4%, 40/1041) spent 150 minutes or more on moderate-intensity physical activity per week, 28% (11/40) of these were women and 72% (29/40) were men. Some 13% (139/1041) of the participants spent 75 minutes or more on vigorous-intensity physical activity per week, 26% (36/139) of these were women and 73% (103/139) men. Walking was the most common leisure-time physical activity engaged in by this population. Figure 1 shows the average MET hours/week from different leisure-time physical activities.

In analysis comparing extreme tertiles, age, religion and marital status were significantly associated with levels of physical activity. Unmarried individuals and those aged less than 30 years were more likely to engage in vigorous physical activity, compared to older persons. These results are shown in Table 2. In multivariate analysis, comparing the lowest (<2 MET h/wk) to highest tertiles (>8 MET h/wk) of physical activity, being married or older than 30 years were associated with higher levels of leisure time physical activity.

In this cross-sectional study of physical activity among urbanized adult Nigerians, we found that 4% of the participants spent at least 150 minutes on moderate-intensity physical activity; while 13% spent at least 75 minutes on vigorous-intensity physical activity. To improve cardiorespiratory and muscular fitness, bone health and reduce the risk of NCDs and depression, the WHO recommends adults aged 18 to 64 years should do at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity activity weekly [4].

Although physical inactivity is common in high and low income countries, its prevalence varies worldwide [3, 33]. Contrary to expectations that physical inactivity is more common in countries of high income because of the level of development than in those of low income, we found up to two-thirds of our study population did not engage in significant leisure-time physical activity [3], where physical inactivity was defined as not meeting any of three criteria: 30 minutes of moderate-intensity physical activity on at least 5 days every week, 20 minutes of vigorous-intensity physical activity on at least 3 days every week, or an equivalent combination achieving 600 metabolic equivalent minutes per week [4, 34]. We also found a high prevalence of overweight and obesity, 74% of the women and 56% of the men were either overweight or obese.

Our results are consistent with other studies in this environment which also found that age, sex, and ethnic origin were associated with physical activity [35]. Previous studies reported that 25–57% of Nigerians were physically inactive [5‐10]. However, the methods used in these studies differ from ours. These studies estimated physical activity as significant physical activity at least once a week [9]; or determined from occupational and leisure physical activity [6‐8]; or used the IPAQ-SF [10]. A systematic review showed that the IPAQ-SF typically overestimated physical activity as measured by objective criterion, by an average of 84% [16]. Nevertheless, the IPAQ is still being widely used to measure physical activity variation globally [17‐21].

Walking was the most common physical activity reported by participants. Walking is a common, accessible, inexpensive form of physical activity and is an important component of total physical activity in adult populations [36]. The comprehensive and neighborhood planning of Abuja facilitates walking and may contribute to the high prevalence of this activity in this study population. Although several studies have shown that neighborhood safety [37], walkability [38], traffic speed and volume [39], and residential density were associated with walking and other forms of physical activity [40], these have not been studied in Abuja. A recent study based on a population in Northern Nigeria showed that perceived safety from crime and traffic were inversely associated with physical activity among Nigerian adults [41].

Dancing was also a commonly reported form of physical activity, especially among women. Given that women are more likely to attend church compared to men [42, 43] and the high proportion of Christians in this population, it is likely that most of the weekly dancing occurs at churches. Studies on church based interventions to increase physical activity among African American women in the United States yielded variable results [44]. Interventions to improve physical activities should consider organizations that serve as foci of community engagement similar to the role of churches among African American populations.

A systematic review showed that adults’ leisure-time physical activity, including sports participation, has increased in five high-income countries in the past 20–30 years [45]. In the study population, men were more likely to participate in soccer, tennis and swimming, compared to women. This suggests that women return home and engage in household chores, while men are more likely to participate in sports or engage in physical activity at health clubs [46]. Efforts to promote leisure time physical activity among populations like urbanized Nigerians may build on activities that are already prevalent in the community like walking and dancing instead of introducing new modalities.

Our study is limited by its cross-sectional design and focus on adults in an urban population, thus the results do not account for leisure-time physical activity among children or individuals in rural populations. However, we objectively measured the characteristics of the study population using standardized guidelines and techniques and measured physical activity using validated tools.

In this population, the proportion of people who engage in leisure time physical activity is low, this has major implications for the prevalence of NCDs in this population. More studies investigating factors associated with physical activity, prevalent and preferred types of physical activities, and intervention studies to increase it should be implemented. Results from such studies may help promote participation in physical activity and support policy choices that can effectively prevent NCDs in African populations.