Temporal Trends in Obesity and Chronic disease risks among Young Adults: a 10-year Review at a Tertiary institution, Nigeria

Background There is an increasing prevalence of obesity among college/university students in developing countries similar to the trend being observed in industrialized countries. Of great concern is the persistence of weight gain among this young population with the risk of being overweight and obese increasing with years of study and till adulthood. The aim of this study is to describe the trend and burden of overweight/obesity and emerging associated chronic disease risks among adolescents and young adults at the University of Ibadan, Nigeria. Method This is a 10-year retrospective review of medical records of students (undergraduate and post-graduate) admitted between 2009 and 2018 at the University of Ibadan, Nigeria. A total of 60,168 participants were analysed. The Body mass index (BMI) categories were determined according to WHO standard denitions and blood pressure was classied according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC7)

Of great concern is the persistence of weight gain beyond the rst year (freshman year) with the risk of being overweight and obese increasing as the year of study increases and till later adulthood. In other words, once established, childhood and adolescent obesity status conferred markedly heightened risks for later overweight and obesity [17,18]. Thus, overweight and obesity in adolescents and young adults have important public health implications, not just about its increasing prevalence, but because of possible long-term associations with future weight status and related morbidity.
Also, while diseases associated with under-nutrition are still a major issue, LMIC are experiencing a marked increase in overweight and obesity associated with rising burden of non-communicable diseases (NCDs). This dual burden of malnutrition places heavy tolls on individuals, families, economies and health-care systems [19,20] in terms of cost of treatment and mortality.
The causes of excess weight gain in young people are similar to those in adults. However, young people are signi cantly prone to obesity due to changes during the transition from childhood/adolescence to adults [17,21], accompanied by the peculiar and signi cant lifestyle changes that occur during the phase of leaving home and going to university/college [22,23].The interaction of social, psychological and biological factors that happen during these transition years, added to the pervading obesogenic environment make them vulnerable to many risk-taking behaviours [24,25,26]. For example, there is preference for energy-dense foods, higher-fat intake and more consumption of sugar-containing drinks. Reduced energy expenditure due to not getting enough physical activity, sedentary activities such as long hours of watching television or other screen devices are also contributory factors in an increasingly urbanized and digital world. The transition to independence of college students, the competing academic demands in the presence of unhealthful lifestyle options and existing environments that greatly favour high energy intake and low energy expenditure provide the complex mix perpetuating the obesity trajectory in the campuses [27].
The rising prevalence of overweight and obesity and lack of physical activity contributes to increasing risks of various chronic diseases in young adults with greater severity in adulthood. Studies showed that risk factors for metabolic syndrome are more prevalent among overweight or obese children and young adults than among those of healthy weight [28,29]. Obesity in childhood or adolescence is associated with higher risk of adult hypertension, coronary heart disease, and stroke [30]. Thus, the increasing prevalence of overweight and obesity among adolescents may be leading to a higher young adult hypertension prevalence that will continue into the future with severe complications. There is a concern that overweight/obesity and associated chronic diseases such as hypertension, Cardiovascular Disease (CVD) and diabetes are fast emerging as the most prevalent NCDs in LMIC prematurely affecting younger people.
The university environment presents a unique opportunity to target young persons for obesity prevention interventions.
The period of stay of young people in the university also offers many opportunities for relevant longitudinal prospective studies and life courses. However, young adults are largely overlooked due to the perception that many in this population are at a low risk of developing chronic diseases. At present, there are limited data to show the temporal trends in the pattern of transition and prevalence of overweight/obesity among university students in Nigeria. Furthermore, there is no evidence of any concerted efforts at stemming the tide of the epidemic. It may as well be that Nigerian universities are unwittingly sustaining obesogenic environment critical to amplifying the biologic vulnerability of young people to obesity. Unlike substance abuse and mental health issues, many college and university leaders may view helping overweight and obese students as being outside the purview of higher education [27]. This may explain why there has not yet been any recorded obesity prevention interventions being conducted in developing countries within or for this age group ( [31]. The aim of this study was to identify and describe the burden of overweight/obesity and chronic disease risks among young adults in University of Ibadan (UI), Nigeria with a view to laying the foundation for a sustainable plan that promotes optimal weight management and future research in obesity prevention and intervention in the institution.

Study design
This was a 10-year retrospective review of medical records of students (undergraduate and post-graduate) admitted between 2009 and 2018 in UI. The study participants consisted of adolescents and young adults who were enrolled as Page 4/22 freshmen for undergraduate studies and those who had returned or enrolled for postgraduate studies in the institution. The medical record review utilized the data of students admitted for each new academic year under review. It consisted of data from the screening routinely done at inception as part of their admission processes and the follow-up data comprised information on any obesity-related diseases that they obtained treatment and care for at the University Health Services (UHS). In this study, adolescent and young adults were classi ed as those from 16 to 40 years of age while those above 40 years and ≤ 65 years were classi ed as adults (middle age and older adults).
Study setting UI was established in 1948 and it is located ve miles (8 kilometres) from the centre of the major city of Ibadan in South-Western Nigerian. It currently runs academic programmes in sixteen Faculties and other academic units among which are: Institute of Child Health, Institute of Education, Institute of African Studies. Also, the University plays host to the Pan African University which runs postgraduate studies.
Each academic year, new students admitted for undergraduate and postgraduate programmes are required to register at the UHS as part of the admission process and for their medical care during their stay in the university. The UHS employs structured questionnaires to collect pre-admission health information including socio-demographic characteristics and background medical (personal and family) history of the students. Physical examination and measurements including pulse rate, blood pressure (BP), height, weight and BMI are also carried out. For this population, the body mass index was derived using the weight and height measures. Weight was measured to the nearest 0.1 kg using a digital scale. Height was measured to the nearest 0.1 cm with a portable stadiometer while the individual stood barefoot on the centre of the base with their back to the stadiometer. The BMI was calculated by body weight (kg) divided by squared height (m2). The BMI was then split into 4 categories: underweight (BMI < 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9) and obesity (BMI ≥ 30) [WHO, 1995]. Blood pressure was measured using a mercury sphygmomanometer based on the recommended standards [32] and classi ed according to JNC 7 [33]. Chest x-ray and urinalysis were carried out as part of the initial medical evaluation. All these and the medical records of subsequent visits by each student to the clinic were documented in the clinic personal le. Information about diagnosis and treatment for obesity-related diseases such as hypertension, diabetes, dyslipidemia, asthma, gall stones were extracted and reviewed retrospectively. Also, the results of relevant investigations such as Electrocardiography (ECG) and lipid pro le were reviewed, where available.

Study population
A total sample consisting of all the medical records during the period of review was collected. Speci cally, all the health records of the newly admitted students during the 10-year period of review (2009-2018) were used for this study. The University offered admission to an average of 3,500 undergraduate students and 3,000 of postgraduate students for each year of admission during the period of review. Therefore, a total sample of approximately 60,168 medical records with complete information was used for this study. The data presented in this study depicts the pro le of a large population of young people from different regions of Nigeria.

Data collection
From June through October 2020, medical records were extracted by trained Research assistants using a standardized excel tool. The outcome variables of interest are overweight and obesity and the covariates are age, sex, background medical (personal and family) history of the students (hypertension, diabetes, asthma, medications), treatment records for obesity-related diseases such as hypertension, diabetes, dyslipidemia, asthma, gall stones and cancers.

Data analysis
The data was entered and cleaned using SPSS 21. Numerical variables such as age, weight, height and blood pressure were summarized using mean (SD) while frequencies/percentages were used for categorical variables. Trends in obesity and hypertension were assessed using Chi square for trend at 5% signi cance level. Independent factors associated with obesity/overweight and hypertension were assessed using multivariable binary logit model. Measures of effect were reported as Odds Ratio with 95% Con dence Interval (95% CI).

Ethical Consideration
This is a retrospective medical record review only with no contact with human subjects. Permission to access and use data from the medical records was obtained from the Management of the University of Ibadan Health Services. All information extracted from the medical records were recorded without identi ers and kept con dential. The need for

Results
Background characteristics Table 1 shows the trends in socio-demographics (age group, sex, programme, BMI and hypertension) of students between 2009 and 2018. A large majority was ≤ 40 years (95.1%). Students aged 16-20 years constituted at least a quarter during the years under review. In addition, the percentage in this age group has been on the increasing trend since 2013 till 2018 while the reverse pattern was observed for age 36 years and above of which their percentage declined. The sex distribution was in favour of males between 2009 (51.5%) and 2011 (53.7%) but this has been reversed thereafter such that males constituted less than 50% since 2015. Overall, undergraduate students constituted 51.9% of the entire sample. However, there were some variations over time with a lowest value in 2011 (35.8%) and highest in 2017 (68.1%) and 2018 (65.8%).  Fig. 3].
The prevalence of hypertension based on systolic (140) and diastolic (90) blood pressure cut-off at enrolment was 8.1%.
The level seems to be on a downward trend since 2015 (11.4%) till 2018 (5.5%) [see Fig. 4].   Medical history and obesity-related health conditions Table 3 shows the medical history and obesity-related health conditions or disease pro le of the students. Over the 10-year period, hypertension is the most prevalent non-communicable disease which is followed by asthma. Thirty ve percent of the study population had pre-hypertension de ned as systolic pressure from 120 to 139mmHg or diastolic pressure from 80 to 89mmHg. About 2.2% of the study population had multiple risk factors for hypertension.   Association between the socio-demographic characteristics of the students and overweight/obesity There is signi cant association between age and overweight/obesity ( Table 4). The percentage of students that are overweight or obese increased as age increases except with students above 41 years who had lower percentage of overweight and obese students compared to those between ages of 31 to 40 years. There is also signi cant association between gender and being overweight or obese with more female students being overweight or obese (30.9%) than male students (21.2%). More postgraduate students were overweight or obese (37.8%) compared to undergraduates (15.0%). The factors that were identi ed to be signi cantly related to overweight/obesity were also subjected to multivariate analysis the results of which are presented on table 5. The likelihood of overweight/obesity increased with age. For instance, students aged 36-40years (OR=5.27) and aged 41 years and above (OR=8.96) were more likely than those aged 16.-20 years to be overweight/obese. The odds of overweight/obesity were signi cantly higher among females than males and postgraduate students [see Table 5]. Association between the socio-demographic characteristics and prehypertension and hypertension Table 6 shows the bivariate association between socio-demographics characteristics of students, prehypertension and hypertension. There was a signi cant association between age, sex and pre-hypertension (p-value <0.05). Furthermore, there is a statistically signi cant association (p-value <0.05) between body weight (overweight and obesity) and prehypertension as a higher percentage of students that were overweight and obese had pre-hypertension (45.9%) compared to normal and underweight students (35.6%). Similar ndings were observed for hypertension. Over the ten-year period, there was a signi cant association between age and hypertension (p-value<0.05). The percentage of students with hypertension increased with age such that those aged above 41 years had most cases of hypertension (29.0%) unlike those aged 16-20 years (5.0%). Male students were also more hypertensive (11.2%) compared to their female counterparts (4.8%) and this difference is statistically signi cant (p-value<0.05). More postgraduate students (10.4%) had hypertension compared to undergraduate students (6.0%) and this difference was statistically signi cant (p-value<0.05). There is a statistically signi cant association (p-value <0.05) between body weight (overweight and obesity) and hypertension as a higher percentage of students that were overweight and obese were hypertensive (14.2%) compared to normal and underweight students (5.9%).
The odds of prehypertension increased with age; students aged 41 years and above were 3 times more likely to have prehypertension compared to those aged 16-20 years (OR=2.17, CI:1.94-2.43) and male students were more likely to be hypertensive compared to females (OR=2.40, CI:2.34-2.52).
Similarly, the odds of hypertension increased with age such that students aged 41 years and above were 7 times as likely as those aged 16-20 years to have hypertension (OR=6.11, CI: 5.29-7.06). Female students were less likely to be hypertensive (OR=0.38, CI: 0.36-0.42) than their male counterparts. Overweight/obesity was also associated with higher risk of hypertension (OR=2.25, CI: 2.10-2.41) [see Table 7].

Discussion
This study describes the burden of overweight and obesity and associated risk factors for chronic, non-communicable diseases among newly admitted students of the University of Ibadan. The study participants consisted of adolescents and young adults who came in as freshmen for undergraduate studies and those who had returned or enrolled for postgraduate studies in the University of Ibadan.

Burden of overweight and obesity
The prevalence for overweight and obesity in this study were 18.7 and 7.2% respectively. Similar studies carried out majorly among undergraduates to determine the prevalence of overweight and obesity in Nigerian universities recorded prevalence rates of 16.2% and 4.8% [34] and 25% and 11% [35] respectively. This nding aligns with the overall prevalence for overweight and obesity in a multi-centre study among low-middle income countries including Nigeria which were 22% and 5.8% [12] and in Ghana, 25.8% and 5.9% respectively [36] In this study, overweight and obesity had signi cant relationships with the older age group, being female and undergoing postgraduate training.
We found a consistently increasing trend of overweight and obesity with age. This trend persists till later years of postgraduate programme depicting increasing risk of obesity at middle age and later in adulthood. This aligns with the ndings from the global study of overweight and obesity in children and adults which showed that in both developed and developing countries, successive cohort from 1980 to 2013 tend to gain weight at all ages and the most rapid weight gains occurred between the ages of 20 and 40 years [37]. The persistence in overweight and obesity till later years of study, despite the rigors of academic work in the university, has also been documented in other studies in both LMIC and industrialized countries [7,12,38]. This is not surprising given the fact that the students are being exposed to an environment of independence, urban lifestyle with unfettered access to fast food, high sweetened drinks and energy-dense foods without investment in built environment for physical activity. Furthermore, previous study showed that university students lack knowledge about healthy food choices and this has negative in uence on their eating habits and nutritional status [39,40]. Where exposure to obesogenic environment persists, students who were underweight are at risk of transition to overweight and obesity across the life course.

Double Burden of Malnutrition
Our ndings revealed a double burden of malnutrition characterized by the co-occurrence of undernutrition along with overweight and obesity. In this study, the female gender had a higher burden of abnormal BMI with co-occurrence of underweight, overweight and obesity similar to studies reported in other LMIC [41,42]. Furthermore, there was an increasing shift from undernutrition to overnutrition at each year of entry of the study participants to the University. The double burden of malnutrition documented in this study is similar to ndings reported among students of tertiary institutions in different geopolitical regions of Nigeria [35,43] and other low-and middle-income countries [12]. According to the World Health Organization (WHO), a double burden of malnutrition can be found at individual level comprising abnormal weight with de ciency of one or various vitamins and minerals; at the household level and at the population level -where there is a prevalence of both undernutrition and overweight in the same community, nation or region [5,44]. Studies emanating from LMIC have documented the coexistence of underweight and overweight within the same family [45,46] and communities [47, [47-49].The occurrence of double burden of malnutrition as found in this study re ects the picture of the general Nigerian population [50] and many developing countries that are experiencing nutrition and socioeconomic transitions [51,52].This strongly implies that environmental, nutrition and socio-economic variables rather than genetic factors are likely responsible for the ongoing dramatic double burden of malnutrition in LMIC.
The double burden of malnutrition is a complex and important phenomenon because of the relationship and biological link between the diverse forms of malnutrition beyond coexistence. For example, a stunted child is more likely to be overweight and/or affected by NCDs as an adult [53]. At the same time, undernutrition in form of nutritional de ciencies is an important underlying risk factor for major communicable diseases and global child mortality [54,55]. Thus, the double burden of malnutrition at a younger age is a silent driver of the double burden of infectious and non-communicable diseases [54] later in life. The phenomenon of dual burden of malnutrition also presents a major public health challenge for the health care system [56].
Our ndings underscore three important points. First is that the burgeoning prevalence and pattern of overweight and obesity across the age groups, from different locations suggest a strong environmental/social causative factor deserving further attention as possible target for intervention. Second, the evidence indicates the need to implement lifestyle-related interventions as part of efforts to halt the progression of obesity and prevent the emergence of chronic disease risks later.
Third, greater success may be achieved in curbing overnutrition if the prevailing environmental and social factors are explored further for appropriate intervention. While diseases associated with undernutrition remain a major concern at the face of economic and social transitions, LMIC are experiencing a marked increase in overweight and obesity. This implies that overweight and obesity epidemic is unrelenting and may soon dominate the risk pro le for chronic diseases if unaddressed. According to WHO, this double burden of malnutrition offers a unique and important opportunity for integrated action on malnutrition in all its forms. There is an urgent need for double-duty actions "which are interventions, programs, and policies that have the potential to simultaneously reduce the risk and burden of under and overnutrition" [5,54] targeted at the University community and country at large.

Obesity-related health conditions
Hypertension was the most prevalent chronic condition among the study participants and its prevalence was 8.1% which is consistent with the prevalence of a study conducted among Ethiopian students where the prevalence was noted to be 7.4% [57]. Studies indicate that 90% of young people with hypertension have primary or essential hypertension which has no speci c cause but well-de ned risk factors [58,59,60]. In this study, hypertension had signi cant relationships with older age group, being a male, undergoing postgraduate studies, overweight or obese and those with a family history of hypertension. As overweight and obesity rates increased among the study population, there was a parallel rise in the prevalence of hypertension across the age-groups. Similar nding has been documented among students of a tertiary institution in Cameroon [38].
Hypertension is the leading cause of death globally and most important risk factor for cardiovascular disease, stroke, and chronic kidney disease (CKD) [33,61]. Available evidence shows that young people with hypertension have similar targetorgan damage such as left ventricular hypertrophy (LVH), microalbuminuria and carotid intimal thickness as older adults with hypertension [62]. LVH is one of the early manifestations and immediate consequences of hypertension. The results of this study showed that only a small proportion of the study participants had Electrocardiography (ECG) done as part of the evaluation for hypertension-related target organ damage. The ECG of about three-quarters of those evaluated revealed LVH. This has to be interpreted with caution because ECG is not validated for diagnosis of LVH in young individuals [63]. A previous study showed that Left ventricular hypertrophy is present in about 20-40 % of children and adolescents with high BP, and represents a compelling indication for starting an antihypertensive drug treatment [64]. LVH and other target organ markers are associated with adverse cardiovascular outcomes and risks for end stage renal disease, retinopathy, ruptured aortic aneurysm, stroke and impaired cognitive function [58,60]. These complications and their consequences are unlikely to be clinically apparent for many years in adolescence and young adulthood. Thus, there is a need to adapt and follow recommended guidelines for the investigation and management of hypertension and co-morbidities in young people.
Also, our study revealed that a third of the study population (35.1%) had prehypertension. Reports from many studies indicate that prehypertension is common among adolescents and young adults with evidence of target organ damage already present. Prehypertension is not considered a disease category, but identi es those who are likely to progress to stage 1 or stage 2 hypertension in the future [65,66] without intervention. It is a strong predictor of hypertension and future cardiovascular disease [67,68]. The signi cant relationship between prehypertension and being overweight and obese in this study implies that the burden of hypertension and cardiovascular disease may increase if the obesity epidemic continues to spiral out of control.

Implications for Interventions
Primary prevention remains the most realistic strategy to curb the growing burden of obesity and obesity-related health conditions among adolescents and young people. This is pertinent considering that overweight/obesity and related health conditions documented among adolescents and young adults in this study predates their entry to the university. Unfortunately, the systematic reviews of studies have reported gaps in the number and quality of obesity prevention interventions conducted within the adolescents and young adult age groups in developing countries [69,70]. Young people represent a unique age group whose views and health needs are not being adequately addressed by the health management information system. For instance, there was apparent neglect of adolescents (with the exception of married female adolescents) during the collection of national data on nutrition during the Nigeria Demographic Health Surveys [50]. In addition, policies and programmes to address nutrition in Nigeria remain skewed towards undernutrition and children under ve years [50,71]. To tackle obesity among Nigerian adolescents and young people, a critical step is the collection of data on its burden, risk factors and trends. Furthermore, there is a need for holistic, synergistic mix of population-level interventions such as the provision of physical activity facilities, coupled with the regulation of labelling, marketing, content and pricing of energy-dense foods and sugar-sweetened beverages which target the obesogenic environment and requires a multi-sectoral approach [71,72].
The strengths of this study include the large population of adolescent and young people from diverse geographical and social background as participants. Population-based studies on obesity and emerging NCD risks are needed to build an evidence base that socially and culturally re ects the reality in developing countries. This is a novel study that included both undergraduate and postgraduate students covering broad spectrum of adolescents, young and middle-aged adults.
Hitherto, studies on obesity and overweight problems were mainly carried out on undergraduate students. The study spans over a ten-year period which shows trends in obesity and hypertension, thus increasing the validity and power of this study. The ndings from this study will add to the body of knowledge on the burden of obesity and overweight among university students both in Nigeria and globally which will assist in planning effective health intervention programmes to reduce the heavy burden of obesity noted among university students.
Key limitations include lack of data on dietary intake, physical activity, socio-economic status, smoking and alcohol consumption and other emerging lifestyle risk factors on obesity and overweight which could provide a richer perspective on the factors contributing to the burden of obesity and associated diseases among this population. In addition, another limitation is the use of ECG and not Echocardiography which is the validated test for the diagnosis of LVH in young individuals thereby limiting the usefulness of LVH nding in this study.

Conclusion
This study has identi ed the burden of double malnutrition, rising trends in the prevalence of obesity among students in a tertiary institution and the emergence of chronic disease risks with a lifelong implication on their health and a concomitant burden on the health system. Evidence-based, cost effective interventions are urgently needed at the secondary and tertiary-level educational institutions to address the growing burden of obesity among this population.
These interventions must be holistic and transcend obesity awareness programmes to include those which target the obesogenic physical and policy environments and empower young people to adopt appropriate healthy behaviours.  Availability of data and materials The datasets are available upon request to the corresponding author. This can only be used for non-commercial purposes while maintaining participants' con dentiality.

Competing interests
The authors declare that they have no competing interests.

Funding
This research was supported through funding from the University of Ibadan.

Authors' contributions
The study was conceived by AOO. MMO, JOA, AJA, ASJ, GD and OOA contributed to the design of the study. The data collection was carried out by OLO, AOO, MMO and JB. JOA, AOO and MMO analyzed the data, AOO, MMO, JOA and OBO wrote the manuscript, AJA, GD and ASJ revised and provided critical review of the manuscript. All authors read and approved the nal manuscript. Trend of Hypertension cases among university of Ibadan students (2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)