Dr. Jørgense[/caption]
Terese Sara Høj Jørgensen PhD
Assistant Professor
Faculty of Health and Medical Sciences
University of Copenhagen
MedicalResearch.com: What is the background for this study?
Response: Dementia may develop as a result of both genetics and environmental exposures operating throughout the life course, and the risk of dementia may already be established early in life. Body height has a strong genetic component and is at the same time influenced by environmental factors early in life. Body height is an expression of growth early in life and a taller body height could express that the body has had an optimal development. At the same time, a shorter body height could be an indicator of harmful exposures early in life. A few smaller studies have identified a link between body height and dementia. However, rather than being a risk factor of dementia in itself, body height is likely an indicator of harmful exposures early in life and hereby linked to dementia. Body growth could furthermore be linked to dementia as an indicator of brain and cognitive reserve. Thus, to understand the relationship between body height and dementia, large scale high-quality longitudinal studies exploring the impact of early environmental factors and genetics to explain the link between body height and dementia were needed prior to this study.
Dr. Khan Mirzaei[/caption]
Dr. Mohammadali Khan Mirzaei
Institute of Virology
Helmholtz Zentrum München
Neuherberg, Germany
MedicalResearch.com: What is the background for this study? Can you briefly explain what is meant by a bacteriophage?
Response: Child stunting a severe growth impairment, globally affecting about 1 in 5 of children. The correlation between altered gut microbiota and stunting is already known. In contrast to what we know about the link between altered gut bacteria and stunting, the role of phages was not explored.
Phages are the bacterial viruses that match the number of bacterial cells by a 1:1 ratio in the human gut. They are central to the biogeochemistry of most ecosystems by driving bacterial physiology, diversity, and abundance. Therefore, we expect a significant role for them in the human gut.
Eirini Marouli[/caption]
Eirini Marouli
William Harvey Research Institute
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London
MedicalResearch.com: What is the background for this study?
Response: Epidemiological studies suggest that shorter stature is associated with increased risk of coronary artery disease (CAD) or type 2 diabetes (T2D). It is not clear though whether these associations are causal or there are other factors mediating these effects. When randomized trials are inappropriate or impossible, we can use Mendelian Randomisation as a good alternative to study the causal relationship between a trait and a disease. Here, we examined over 800 places in the human genome known to be associated with adult height and evaluated how genetically predicted height can affect the risk of CAD or T2D. Furthermore, we evaluated the role of several risk factors including, cholesterol, triglycerides, blood pressure, body mass index, fat percentage, socio-economic parameters including education and income as well as lung function. Lung function was assessed by spirometry measures including FEV1: forced expiratory volume in 1 second, FVC: forced vital capacity.
Dr. Limony[/caption]
Yehuda Limony, MD, MSc
Pediatric Endocrinology Unit
Faculty of Health Sciences
Ben-Gurion University of the Negev
Clalit Health Services
Beer-Sheva, Israel
MedicalResearch.com: What is the background for this study?
Response: The variability of the onset age of puberty is the subject of many studies in numerous disciplines; nonetheless, the timing of puberty remains an enigma. The conventional paradigm is that the time of onset of puberty is genetically determined even though genome-wide association studies explain only a very low percentage of the physiologic variability. It is commonly believed, therefore, that many environmental factors interfere with the genetics of timing of puberty.
On the other hand, children grow toward an adult height that is the standardized average of parents' height called "target height". That is why children are usually similar in height to parents. This targeted growth process is evident especially in children whose height percentile in childhood is different from their target height percentile (we called this difference the "height gap"). It is known that the timing of puberty is associated with adult height: earlier puberty causes shorter adult height and vice versa. We hypothesized that the targeted process of growth involves adaptation of the age of onset of puberty in accordance with the height gap.
Dr. Duren[/caption]
Dana L. Duren, PhD
Professor, Director of Orthopaedic Research
Director of Skeletal Morphology Laboratory
Thompson Laboratory for Regenerative Orthopaedics
Department of Orthopaedic Surgery
Missouri Orthopaedic Institute, University of Missouri
Columbia, MO 6521
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The motivation for this study is the apparent accelerated maturity in children in the United States.
[caption id="attachment_46650" align="alignleft" width="139"]
Radiogram of distal tibia (left) and fibula (right) showing two epiphyseal plates.
Dr. Vuoksimaa[/caption]
Dr. Eero Vuoksimaa PhD
Institute for Molecular Medicine
University of Helsinski
Finland
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: There are many previous reports indicating a positive association between height and cognitive ability but the underlying mechanisms behind this correlation are not well known. We used a mediation model to test if this association is explained by brain size as measured with cortical grey matter size.
We found that total cortical surface mediated the relationship between height and cognitive ability.
Prof. Majid Ezzati[/caption]
Prof. Majid Ezzati, PhD
Faculty of Medicine, School of Public Health
Chair in Global Environmental Health
Imperial College, London
Adjunct Professor of Global Health and
Department of Global Health and Population
Harvard T.H. Chan
School of Public Health
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Human height is strongly influenced by the environment that we grow up in, from pregnancy through to late adolescence. If we have good nutrition, few illnesses and good healthcare, we are more likely to grow taller. In turn, height has a strong effect on our health in adulthood. Taller people on average live longer, have lower risk of heart disease (although they do have slightly elevated risks of some cancers).
We have collated the largest-ever database of height. We analysed 1472 studies with measured height on 18.6 million individuals. We made estimates of height for 18-year-old men and women from 1914 and 2014. Height has increased in every country in the world, but this has been very uneven. The tallest men in the world are now the Dutch, and the tallest women are the Latvians. The countries that have seen the most growth are South Korea for women and Iran for men. We have seen large increases in height in East Asia, and stagnation in much of the West over the last few decades. In parts of Africa height has actually decreased by 5-10 cm over this period.
Prof. Norbert Stefan[/caption]
Prof. Norbert Stefan, MD
Department of Molecular Epidemiology
German Institute of Human Nutrition
Potsdam-Rehbruecke
Nuthetal, Germany
MedicalResearch: What is the background for this study?
Prof. Stefan: Cardiovascular disease, type 2 diabetes, and cancer are among the most important causes of morbidity and mortality worldwide. Although the body mass index and waist circumference are established variables that help to predict the risk of these disease, adult height also predicts mortality independently of adiposity measures. However, compared to these risk factors, it has been somewhat neglected in clinical practice. Based on the finding that in recent decades the height of children and adults has steadily increased throughout the world, the question arises whether this secular trend in height might be a marker of a yet not well understood mechanism that affects not only stature, but also the development of cardiometabolic disease and cancer.
MedicalResearch: What are the main findings?
Prof. Stefan: We summarized and interpreted data from different areas of research and also could provide some novel data to better understand the causes of the worldwide increase in height and its relationships with cardiometabolic disease and incidence of cancer. There is strong epidemiological evidence that tall people, in comparison to short people, have a lower risk of cardiovascular disease and type 2 diabetes but have a higher cancer risk. Per 6.5 cm in height the risk of cardiovascular mortality decreases by six percent, but cancer mortality, by contrast, increases by four percent. We suspect that the increase in body height is a marker of overnutrition of high-calorie food rich in animal protein during different stages of growth. Thus, already in utero, lifelong programming might take place that until now has mainly been established for the insulin-like growth factor 1 and 2 and the IGF-1/2 system. Among other consequences, activation of this system causes the body to become more sensitive to insulin action, thus positively influencing the lipid metabolism. Accordingly, our new data show that tall people are more sensitive to insulin and have lower fat content in the liver, which may explain their lower risk for cardiovascular disease and type 2 diabetes. However, this activation of the IGF-1/2 system and other signaling pathways may be related to an increased risk of certain cancers, especially breast cancer, colon cancer, and melanoma because cell growth is permanently activated.
MedicalResearch.com: Interview with:
Dr. Aaron P. Thrift PhD
Public Health Sciences Division
Fred Hutchinson Cancer Research Center
Seattle, WA.
Medical Research: What are the main findings of the study?
Dr. Thrift: We conclude that height is inversely associated with risk of esophageal adenocarcinoma, both in men and women. The association is not due to confounding from known risk factors or bias.