YOUNG RESEARCHERS. At the population level, he sees the connection between sex hormones and other risk factors for asthma and allergies. By understanding the mechanisms at the cellular level behind his statistical findings, he hopes to find new treatments. Bright Nwaru has been recruited as an epidemiologist to the Krefting Research Centre within the framework of the Wallenberg Centre for Molecular and Translational Medicine (WCMTM).
I meet Bright in his office at the Krefting Research Centre, located on the ground floor in the middle of Medicinarlängan. Bright is one of the researchers here working on a broad front to understand the causes and risk factors behind asthma with the goal of preventing the disease and contributing to finding better treatment for asthma patients.
Breastfeeding advice called into question
Bright has lived in Europe for 15 years. He received his undergraduate education in public health in his native Nigeria and has two master’s degrees: one from Norway and one from Finland. He defended his doctoral thesis at the University of Tampere, Finland, and has managed to serve as a postdoc in both Finland and the United Kingdom before taking a position within WCMTM here in Gothenburg. Up to now his team has consisted of a postdoc and himself, and he’s now in the process of recruiting his first doctoral student in Gothenburg.
“I am extremely happy here. Through WCMTM, I’ve been introduced to interesting research platforms and collaborations that make it possible to conduct exciting and relevant research,” says Bright, who also is associated with researchers at AstraZeneca, where he uses Swedish registers to calculate the incidence of asthma and allergies in Sweden. “My goal is to understand the mechanisms behind the statistical connections I can see at the population level.”
Early foodintroduction reduced allergy
In his thesis he has investigated how the risk of asthma and allergies in children is affected by what the mother eats during pregnancy and the breastfeeding period. Bright says that the diet during prenatal life and infancy has very great significance: “We were among the first to question the advice that new mothers should breastfeed their children exclusively for four to six months, and only then begin to introduce the baby to solid foods, in order to prevent the development of allergies. We could see that children who previously had been allowed to try foods other than breast milk at as early as three months had better protection against asthma and allergies. New parents are often advised to start giving their babies one type of food at a time, but as a postdoc I and my colleagues could see that from the point of view of allergies, it seems to be better to blend, to mix together different vegetables and other foods in the baby’s purées.”
He is not at all negatively disposed to breastfeeding. On the contrary, he believes that breast milk is great for newborn babies. But at the population level, the risk of allergies and asthma can decline if solid foods are introduced earlier to the child who is still breastfeeding. “What we have done are observational studies, in which we see that children who are allowed to eat solid foods earlier develop allergies and asthma to a lesser extent. We still have not done mechanistic studies that can tell more about the ramifications for the immune system in the case of children who are breastfed exclusively for long periods and of children who also receive solid foods at an early stage.”
Continuing to follow children in the study
Bright is a father of three children himself, with one child less than six months old who is solely breastfed and has also developed eczema. But as a parent, he says, it is important to remember that allergies and asthma in individual children may have many, sometimes interacting, causes.
“It’s not easy to change the recommendations that apply, and first more research in this area is needed. For example, it may turn out that even if children who are allowed to try normal food earlier are less prone to allergies and asthma, they may at the same time be at increased risk of type 1 diabetes. Therefore, we must first understand the mechanisms behind these findings.”
The population study on which he based his thesis was started during the 1990s in Tampere, and Bright’s results have later been confirmed in studies performed in other population studies. He is now an adjunct professor of epidemiology at the University of Tampere, where he and his doctoral students continue to follow up the same cohort as the one in his doctoral thesis.
The role of sex hormones
Among children, asthma is less common among girls than among boys, but in adulthood it is much more common for women to develop asthma than for men. For this reason researchers have long suspected that sex hormones may play an important role in the development of asthma. In an article published early this year in the Journal of Allergy and Clinical Immunology, Bright and his colleagues could demonstrate that girls who get their first menstrual period early, before the age of 11, had a 40 percent higher risk of developing asthma.
“This indicates that the change in hormone levels in some way affects the immune system, but we don’t yet know how. We need to follow up with mechanistic studies,” says Bright, who, among other things, is collaborating with Claes Ohlsson and other colleagues at the University of Edinburgh and Kings College London in work involving sex hormones and the risk of asthma and allergies.
He is doing additional work now at Krefting Research Centre on the link between sex hormones and asthma among women. One resource is the West Sweden Asthma Study, a population study that encompasses randomly selected people in the Västra Götaland region ages 16 and up. This population study has been under way for 10 years now and includes a wide variety of tests and measurements from the study participants. It also notes which of the women participating in the study have been treated with various kinds of sex hormones.
Other researchers have pointed to markers in genetic studies that are linked to the age at which women enter menopause, and the function of these markers are now being examined in the Swedish cohort: “If we can show that these genetic markers play an important role in the risk of developing asthma, then they can also be targets for new treatments.”
TEXT AND PHOTO: ELIN LINDSTRÖM CLAESSEN
