This is the first study of rural adolescents in Nigeria to establish the prevalence of a wide range of modifiable CVD risk factors. The findings showed adolescents have a wide range of unique clustering patterns and the most common clustering pattern was a high animal lipid and salt diet.
Demographics
We have captured about 60 % of the school going adolescent population from this rural region on Nigeria. However, since some rural adolescents do not attend schools, our findings may not be applicable to adolescents who are not attending schools. Regarding adolescents attending schools, we think, adolescents who did not participate might not have provided very different responses because the rural adolescents in our study had similar socio-economic backgrounds and environmental exposures.
More females participated in the study than males. This is because absenteeism from school was more common among male adolescents resulting in more females being available to participate in the study. Reasons for male absenteeism at school were not explored in this study. Many questionnaires were not used for analysis because they were over 18 years. Many of the adolescents in senior classes were over 18 years because many rural adolescents start school late and some have academic challenges. Therefore they spend more time in high school than expected. Implications of this problem is not within the scope of this study.
CVD indicators
Many adolescents in this study had CVD indicators such as chest pain during exercise and chest pain even at rest. Many of the adolescents had close relatives seeing a doctor for CVD and this could possibly indicate that familial factors may play a role. It is also important to note that chest pain could hinder the participation in physical activity. Though CVD indicators are not the focus of this paper, it will be explored in detail in a related paper.
Clustering of CVD risk factors
The majority of adolescents had more than one CVD risk factor. This is a very high prevalence of clustering of CVD risk factors among these rural adolescents. Clustering of CVD risk factors here refers to adolescents having more than one risk factor. Clustering of CVD risk factors exposes an individual to a greater risk of CVD than having a single risk factor. The presence of clustering of risk factors for CVD indicates the need for concerted efforts for reduction and prevention of CVD risk factors among these rural adolescents. According to Commerford and Mayosi [28, 29], low prevalence of CVD in Africa in 2006 presented a unique opportunity for primordial prevention of CVD in Africa. Presently CVD is increasing in Africa and atherosclerotic risk factors are increasing both in certain rural and urban areas [29], however rural people especially adolescents could still benefit from primordial and primary prevention.
It is important to note that a wide range of clustering patterns was reported. This may imply that the clustering patterns are still developing during adolescence and that more consistent and persistent patterns will emerge at a later stage as the adolescents grow into adulthood.
Nutritional clustering pattern
Poor dietary pattern was the most prevalent CVD risk factor observed among the adolescents in this community. A diet consisting of high animal fat diet and salt consumption was the most common clustering pattern. Adolescents in this study have established poor dietary patterns as seen in other studies [30, 31]. In the past, rural dwellers in Nigeria had good dietary patterns compared to the city dwellers. The findings from this study show that young people are no longer continuing with cultural and local dietary pattern probably because of urbanization. Adverts from media promote western diets and young people may think this pattern of feeding is associated with civilization and affluence. High salt intake is a risk factor to hypertension and food rich in animal lipid is a major risk factor for developing CVD. Many of these adolescents might migrate to urban areas either for studies or for better employment opportunities. Hence, their diets will contain even higher levels of animal lipids and salt. There is therefore the need for CVD prevention programs before urbanization.
Current smoking
The prevalence of current smoking observed in this study is low compared to the ones observed in advanced countries [12–14]. This is encouraging though one in every ten adolescent males is a smoker (Table 2). The majority of the adolescents have tried smoking at one time with more adolescents males trying smoking than females and some may have the intention to smoke more in the future. This intention to smoke could be influenced by advertisements in the media where smoking is associated with stardom and rural adolescents feel smoking is one of the ways of showing greatness and affluence. This implies that adolescents in this study may smoke once they have the opportunity. This finding supports the findings of Muula and Mpabulungi [32] who observed that many young people are picking up the smoking habit in Africa. The fact that few of the adolescents are current smokers in this study may be due to poverty, as the majority has tried smoking and some intend to smoke in the future. There is a need for an educational program to educate rural adolescents in Nigeria about the dangers of smoking. This we believe could be built into CVD prevention programs for rural adolescents.
Alcohol
The excessive alcohol use among these adolescents was low compared to data from advanced countries [33, 34]. This could be because hazardous drinking brings stigmatization and it is against cultural values especially in the south west. However, there is a high level of poverty in this rural community, as such this may affect the level of alcohol consumption. However, the finding implies that one in every ten adolescents consumes alcohol at a level that is detrimental to health. This calls for concerted effort to address the issue and prevent further problems.
Physical activity
Many of the adolescents had low levels of physical activity. This is in agreement with WHO findings which show that less than one third of adolescents globally are active enough to safeguard their future health. It also supports findings among US adolescents [35, 36]. It also corroborates the study among suburban adolescents in Nigeria [14]. It is believed generally in Nigeria, without empirical data, that the rural people are adequately physically active. This finding negates this belief. Low physical activity observed in this study is quite high though not as high as observed in developed countries. Low physical activity observed in this study may be enhanced by school curriculum, evident in lack of physical education in many schools and the adolescent lifestyle of hours spent in watching TV and playing video games with no planned/voluntary participation in physical activity program. Physical education in schools needs enhancement through national school policy as done in developed countries and even some developing countries. There is a need to explore why physical education is not included in the school time table and where there is physical education on the time table, why there is no implementation. High rates of CVD are inevitable unless there is an urgent prevention program put in place.
Obesity
Prevalence of overweight or obesity among our study participants was low compared to findings from developed countries [11–13]. While obesity is low now among these rural adolescents, with sedentary living and poor dietary pattern of high animal fat diet and fried food preference, given a short time and poverty alleviation, obesity might become a serious concern as it is in advanced countries now, therefore prevention programs are needed. More females were obese. This corroborates studies which report prevalence of overweight and obesity more in females than males [37, 38]. It is important to note that women are expected to be fat as a sign of good health and good nourishment in many rural areas in Nigeria; therefore many rural Nigerians are not likely to see overweight and moderate obesity as a problem. This calls for health education for rural adolescents.
Abdominal obesity
Abdominal obesity was observed in this study. Abdominal obesity has been found to be strongly associated with CVD in previous studies [39, 40]. Some of the adolescents had waist hip ratio above normal. This implies prevalence of abdominal obesity among this rural adolescents. It is however, surprising to see that adolescents who have normal weight and even underweight had abdominal obesity. This could be protein malnutrition but high calorie resulting in storage of excess fat and calorie in the abdomen. Abdominal obesity predicts CVD risk.
Prevalence rate of CVD risk factors between male and female adolescents
Excessive use of alcohol and smoking were significantly higher in male adolescents than female adolescents while obesity and physical inactivity were significantly higher in female adolescents than male adolescents. The finding from this study on smoking prevalence and sex contradicts findings from GYTS study which observed more smoking among female than male adolescents in Ibadan, a city in south west Nigeria [41]. This could be because this study was conducted among rural adolescents who may still be influenced strongly by cultural values in contrast to the adolescents in the GYTS study who live in urban areas and are becoming more westernized in their lifestyle. In Nigeria women are not expected to engage in drinking, in fact it is almost a forbidden thing for a woman to drink alcohol in public places like restaurants especially in rural areas. Smoking is also associated with sex because women are virtually forbidden to smoke; smoking in women is linked with social vices such as prostitution. This may be the reason for alcohol and smoking being significantly higher among male gender in this study. However, it is important to note that smoking and alcohol did not have 0 % prevalence among female adolescents. This implies that young girls even in rural Nigeria are dropping some traditional beliefs and picking up some westernized lifestyle. Low physical activity and obesity were significantly higher in females. This may be because women are expected to be fat and girl child in rural Nigeria grows up believing that she needs to be fat. Also low physical activity was significantly associated with female adolescents. The need for holistic and comprehensive and gender related CVD prevention program in rural Nigeria is indicated.
Limitations
Future research should also involve rural adolescents who are not attending schools and those who attend school but are not proficient in English or a local language to complete the questionnaires. This will improve the generalizability of the findings. All responses were self-reported in our study. Risk factors such as salt intake may need a different strategy. In Nigeria, it is routine to add salt while preparing food. However, future studies may need to engage parents or caregivers who prepare food to obtain more insight regarding the amount of salt added. In addition, we also did not consider salt included in processed food. Another limitation was that we did not interpret any “animal lipid” as lean. Although consumption of lean meat in Nigeria is uncommon, it should be considered in future research. In our study, we did not measure level of physical activity (or level of fitness) objectively and this is recommended in future studies. Although we have tested the psychometric properties of the questionnaire, we did not test reliability of the objective measures and this should be done in future research. In addition, for our study we included the use of adult cut off for abdominal obesity.