Charles Rotimi


INTERVIEW: Why hypertension among black people is higher in urban areas – U.S.-based Nigerian Scientist Charles Rotimi

By Bunmi Fatoye-Matory

April 02, 2018

Charles Rotimi is a scientist and Director, Center for Research on Genomics and Global Health, National Institutes of Health, Washington. Dr. Rotimi and co-author Dr. Daniel Shriner just published a study that used whole genome sequence, that is the order of the entire DNA building block of an organism, to provide new insight into the African origin of the Sickle Cell mutation. Inheriting two copies of this mutation leads to sickle cell anemia, a disease that is very common in Africans and other global populations that have had to survive the ravages of malaria. Having one copy of this mutation is protective against malaria. This new study by Mr. Rotimi has profound effect on the understanding, diagnosis and treatment of the disease around the world. Bunmi Fatoye-Matori interviewed him to share his findings and his ideas on how Nigerians could benefit from cultivating a culture of scientific thinking.

PT-Bunmi: Where were you born and raised?Dr. Rotimi: I was born in Benin City, Nigeria. I completed my elementary school and secondary education there. I attended Western Boys’ High School and finished in 1974. I then attended the University of Benin and studied Biochemistry, graduating in 1979. I did my national service in the General Hospital in Port Harcourt. I taught grammar school chemistry in Benin City before emigrating to the United States.

PT-Bunmi: Why did you leave for the U.S.?Dr. Rotimi: To further my education. At the time, I was interested in both Biochemistry and Petro-Chemical Engineering. I got admission in the U.K. for Chemical Engineering, but I chose the U.S. where I got admitted to study Biochemistry. The tuition was also much cheaper in the United States. Then, the naira was stronger than the dollar. The school fees was about ten thousand dollars, about seven thousand Naira, at the University of Mississippi where I studied and graduated with Master’s degree in Health Care Administration from the School of Pharmacy. I went back home in 1985 to use my training to contribute to Public Health in Nigeria. But I couldn’t find a job and I almost ran out of money. So, I left Nigeria and went back to school at the University of Alabama where I did a second Masters in Public Health in Epidemiology. After that, I was accepted into the Ph.D. program at the University of Alabama in Birmingham. I conducted research and trained in epidemiology, statistics and genetics. I did my post-doctoral fellowship at the Loma Linda University in California. It’s a Seventh-Day Adventist University. When I was there, I saw an advertisement, placed by the scientist Dr. Richard Cooper, who would later become my mentor at Loyola University in Chicago. He was looking for an Assistant Professor. His research was about cardiovascular diseases which include hypertension, diabetes and obesity in people of African descent globally. When I saw the ad, I said the person who wrote it had me in mind. It was exactly what I wanted to do. I applied for the job. I went for an interview and I was given the job right away.

PT-Bunmi: Tell me more about Dr. Cooper.Dr. Rotimi: Richard Cooper is a white American who grew up in Arkansas, the son of a physician. He is a cardiologist and epidemiologist, interested in public health. When he was growing up, he saw a lot of disparities between how black and white people were treated. He has always been curious about how racism impacts health, how social factors in society affect people’s health negatively. He was interested in why diseases vary so much as you go across different populations with African ancestry, whether they are living in South America, rural or urban Africa, New York, Chicago, or Kingston. I, too, wanted answers. I moved to the Maywood Neighborhood, which is a Western suburb of Chicago. That’s the location of the Loyola University Medical Center. As the lead scientist of the project, Richard had established a very good team of investigators in the United States, Nigeria, Cameroon, Jamaica, St. Lucia, Barbados, and Manchester in the United Kingdom.

PT-Bunmi: What were your findings about hypertension in black people?Dr. Rotimi: In our study of over 10,000 persons living in urban and rural areas, we found that hypertension increases almost in a monotonic fashion from rural to urban areas. For example, the rate of hypertension is seven per cent in Igbo Ora to 16 per cent in Ibadan and to 26 per cent in the Caribbean nations, and to 34 per cent among African-Americans in the Chicago area. These are all people who share African ancestry but live in very different environment with different diet and lifestyle. We observed that these populations experienced very different rates of hypertension. Some of the reasons for different rate of hypertension observed in these populations include the consumption of salt which increases with urbanisation, excess weight gain and reduced physical activities. There is also less psycho-social pressure on rural people. Racism is a psycho-social factor, for instance, that is more common in the Americas and Europe and disproportionately affects African ancestry individuals living in these societies. When I was in Nigeria, I wasn’t aware of what racism means. I had no consciousness of it at all. But after living here now for decades, one begins to understand how it affects people’s health. In our study, we focus on things we can measure. Other people study the social factors. We could not explain all the differences in the rate of hypertension by the lifestyle and cultural factors that we measured. Genetic factors are also important. I wanted to understand epidemiology and genetics, so I got more training at Loyola. I wanted to know how genetics and environment come together to increase susceptibility or resistance to diseases. For example, some persons consume high salt diet and develop hypertension and others are not very responsive to similar high salt food.

PT-Bunmi: The New York Times recently did a long article about your study on Sickle Cell Disease. Could you say more about this? Dr. Rotimi: In the Sickle Cell Study, we wanted to shed new light on the origin and clinical classification of the disease because these issues have been debated for over forty years. Why haven’t we made progress so that physicians can treat people more effectively? We wanted to use genomics to bring new thinking to these issues.

Bunmi: You and your colleagues carried out this study at the National Institutes of Health (NIH), in Washington, DC. Did you leave Loyola?Dr. Rotimi: Yes, I left Loyola for Howard University in Washington DC. Howard is one of the oldest black universities in America. I was invited by Professor Georgia Dunston, a professor of Microbiology and Genetics at Howard University. She is a very brilliant African-American scientist who got into genetics early. She had the great idea to establish a Genome Center at Howard and was looking for someone to lead it and make it a success. She recruited me for the position and I left a wonderful and secure position at Loyola to take the risk of becoming an independent researcher, to become the Director of National Human Genome Center at Howard University. Howard was established in 1867, a top institution for over 100 years, a wonderful place to understand the genetics of African people all over the world, how genes interact with environment and social experiences. I was there from 1999 to 2008 and then left for the National Institutes of Health. One thing I want to emphasise here is that young people who are in training for any kind of job or profession need mentoring. It is extremely important. While I was at Howard, I got to know Dr. Francis Collins, a physician, geneticist, and one of the leaders of the Human Genome Project. He is now the Director of the NIH. As a young physician, he went to Nigeria as a missionary and worked in Yorubaland. He saw a bit of diabetes. That stayed with him for many years. Georgia Dunston spent some time in his lab at NIH and that was how they both dreamt up a project to study diabetes in Africa (Nigeria, Ghana and Kenya). They invited me to run it as the Lead Investigator. We established three centers in Ibadan, Lagos, and Enugu in Nigeria, Accra and Kumasi in Ghana and Eldoret in Kenya. The study on the genetic basis for Type 2 diabetes has been going on now for almost twenty years. This study has discovered many genes that have important implications for diabetes and related health conditions such as obesity, hypertension, eye disease and cholesterol. Just like other different populations around the world, different environmental pressures shape our genome, like climate, diet, infectious diseases. We have not studied people of African ancestry enough to know how these factors have shaped the structure of their genetic (DNA) inheritance. We now have these Genomic tools to understand the evolution of certain diseases in different populations. In the United States, African-Americans have higher rates of diabetes than Euro-Americans but African-Americans who live in the rural areas have a lower rate of diabetes than their urban counterparts, meaning that genetics alone is not a determinant of disease. Environment plays an important part. Urbanisation increases the risk of these diseases and consuming food in high salt and calories, with less physical activity. The urban environment is more stressful. Take Lagos for example. Some years ago, I visited home. I saw a brand new Mercedes driving past one of the markets where the garbage had not been collected for a long time. Things like this have implications for health. It’s tragic that instead of the elites addressing the living conditions, they run abroad for medical care, and some of them discover that Nigerian doctors are their health care providers in these hospitals abroad! What this means is that the problem is not the training of our doctors but the lack of access to good facilities and our hospitals are not well funded and managed.

PT-Bunmi: What did the Sickle Cell Study reveal?Dr. Rotimi: Sickle Cell has been around for a long time, mainly with people whose ancestors survived malaria in areas where it was endemic. It is not an African disease. It’s in Greece, the Middle East, and India. It developed as a protection against the dangerous consequences of malaria. There had been a debate that the mutation occurred in different locations, that it had a linguistic and geographical spread. Mutations were in categories such as Arab/India, Senegal, Central Africa Republic and Benin. Haplotypes that do not fit into any of these were called atypical. As a result, there is a lack of clarity in diagnosing the severity of the diseases. In our study, we defined a new classification system that simplified the old system into three clusters instead of five. All the atypical are now classified into the three new categories. We have resolved a forty-year debate on whether Sickle Cell is multicentric or unicentric. Our data show that the mutation occurred 7,300 years ago in Africa, when the Sahara was still wet and green. The old ethnolinguistic classification overlapped with each other. For example, we showed that the Arabian/Indian, Cameroon, and Central African Republic haplotypes belong to the same cluster. If this is confirmed, this finding will have important implications for how doctors classify disease severity and how patients are treated. It will likely help doctors understand why someone is having a severe case when he should be having a mild one. Thus, our classification holds the promise of helping doctors to diagnose Sickle Cell better. We encourage the scientific communities in Africa and abroad to study this new classification system to see how it may impact their clinical practice as described on our website at Finally, we identified a new set of 27 genetic markers inherited with the sickle mutation that may influence disease severity.

PT-Bunmi: As a scientist on the global stage, what is your advice for the teaching of science in Nigeria?Dr. Rotimi: We need to get our young men and women to understand and appreciate the fundamentals of science, to appreciate its philosophy, that science is a process. It is an incremental acquisition of knowledge. It’s not a question of saying this is the truth or not. It is not faith, it is data driven. You need to do rigorous collection and analysis of data that could be replicated by other scientists. I think that the uncritical transition from religious thinking to science is affecting how young people think of science in Nigeria and how they ask or not ask scientific questions. They are looking for a gospel truth and not a process. I have nothing against religion, but there is a place for everything. I saw people conducting prayers and Bible study at a teaching hospital in Nigeria during office hours while patients are waiting for care. Just as important, our government needs to support scientific research. What is the proportion of the national budget devoted to funding scientific research in Nigeria? My understanding is that it is very inadequate, perhaps less than one per cent. Opportunities need to be created for young science researchers to work and thrive, they also need to be exposed to international scientists. How we evaluate our scientists is also very important. The promotion of an unqualified person, say to the rank of a professorship, affects the whole system of scientific evaluation and accountability. We don’t have a process of post-doctoral training. People graduate and immediately go into practice or become faculty members before they are fully qualified.

Bunmi: Are you involved with any scientific organisations in Africa?Dr. Rotimi: Yes. I was the founding president of the African Society of Human Genetics with membership in over 20 countries in Africa, USA and Europe. I provided the scientific leadership for the establishment of a large pan-African initiative that is using genomic, epidemiologic and clinical tools to understand health in African peoples. This lifetime achievement established what is known as the Human Heredity and Health in Africa (H3Africa) initiative that began under the umbrella of the African Society of Human Genetics, with me as the President. With over 100 million-dollar funding from the NIH and the Wellcome Trust, the H3Africa initiative has created pan-continental networks of labs that are applying leading-edge research to the study of genetic and environmental basis of disease susceptibility and drug responses in Africans. This initiative is training hundreds of African scientists in state-of-the-art laboratories across Africa and the world. For this effort, I received the NIH Director’s Award. In order to sustain this wonderful project currently funded by international organisations, it is important for African governments and businesses to step up to support its funding. Overall, I am very proud of my efforts to bring diversity to genomics and to use genomic tools to shed light on disease etiology in global populations that will otherwise be under-represented or not represented at all.

PT-Bunmi: You are married to an African-American woman.Dr. Rotimi: Yes, we’ve been married for 32 years. We met way back in college at the University of Mississippi.

PT-Bunmi: What do you think of the conflicts that sometimes arise between African immigrants and African-Americans?Dr. Rotimi: Yes, it’s an old tension, that is sometimes justified, other times not. People relate to each other based on their experiences. But I’ll say this. It is important for people of African descent to know that for them to have respect and full status, they must work together. Africa needs to be developed. Once your homeland is organised, you will be respected. But if your homeland is not respected, individuals, no matter how accomplished, will always fight for respect. If I only get respect as an excellent basketball player on the court, but once I’m on the street, the police brutalise me or members of family and community, that is not respect. Or if I’m given respect as a scientist while standing on the podium, but as soon as I step on the street, I’m assaulted by the police, that is not respect. I say Africa has to be developed for black people all over the world to have respect because of examples from people like the Japanese who were discriminated against for a long time until the rise of Japan as a major global economy. It is very important for Africans in the USA and at home to be careful how they criticise African Americans because we Africans may not have full appreciations of all the social and culture factors African Americans have had to deal with and continue to deal with just to survive.

Bunmi: As a parent, what advice would you give immigrant parents in the U.S.?Dr. Rotimi: Parents must understand the society we live in here. We need to guide our children for them to be aware of the realities in the society we live in so that they are not shocked when they are sometimes not treated equally as their white counterparts. They may experience unequal treatment or denied equal opportunities just because of the color of their skin. If they are with their friends who are of non-African ancestry, and the police targets them, they shouldn’t be annoyed but do all they can to survive. We, parents, also must transfer learning, education, and wealth systematically to the children. This is missing right now. Children should build on the success of past generations, and not having to start all over again. Also, parents should take their children to visit their ancestral homes so they will be familiar with the culture. It is very important. I did this with my older children, but not so much with the younger ones. Home culture helps to build a more aware and well-rounded person.