How might fathers influence the health of their offspring?

Dr Gemma Sharp, Senior Lecturer in Molecular Epidemiology

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A novel thing about the Exploring Prenatal influences On Childhood Health (EPoCH) study is that we’re not just focusing on maternal influences on offspring health, we’re looking at paternal influences as well.

One of the reasons that most other studies have focused on maternal factors is that it’s perhaps easier to see how mothers might have an effect on their child’s health. After all, the fetus develops inside the mother’s body for nine months and often continues to be supported by her breastmilk throughout infancy. However, in a new paper from me and Debbie Lawlor published in the journal Diabetologia, we explain that there are lots of ways that fathers might affect their child’s health as well, and appreciating this could have really important implications. The paper focuses on obesity and type two diabetes, but the points we make are relevant to other health traits and diseases as well.

The EPOCH study will look at how much paternal factors actually causally affect children’s health. Image by StockSnap from Pixabay

How could fathers influence the health of their children?

These are the main mechanisms we discuss in the paper:

  • Through paternal DNA. A father contributes around half of their child’s DNA, so it’s easy to see how a father’s genetic risk of disease can be transmitted across generations. Furthermore, a father’s environment and behaviour (e.g. smoking) could damage sperm and cause genetic mutations in sperm DNA, which could be passed on to his child.
  • Through “epigenetic” effects in sperm. The term “epigenetics” refers to molecular changes that affect how the body interprets DNA, without any changes occurring to the DNA sequence itself. Some evidence suggests that a father’s environment and lifestyle can cause epigenetic changes in his sperm, that could then be passed on to his child. These epigenetic changes might influence the child’s health and risk of disease.
  • Through a paternal influence on the child after birth. There are lots of ways a father can influence their child’s environment, which can in turn affect the child’s health. This includes things like how often the father looks after the child, his parenting style, his activity levels, what he feeds the child, etc.
  • Through a father’s influence on the child’s mother. During pregnancy, a father can influence a mother’s environment and physiology through things like causing her stress or giving her emotional support. This might have an effect on the fetus developing in her womb. After the birth of the child, a father might influence the type and level of child care a mother is able to provide, which could have a knock-on effect on child health.
There are lots of ways in which fathers might influence the health of their offspring. This figure was originally published in our paper in Diabetologia (rdcu.be/bPCBa).

What does this mean for public health, clinical practice and society?

Appreciating the role of fathers means that fathers could be given advice and support to help improve offspring health, and their own. Currently hardly any advice is offered to fathers-to-be, so this would be an important step forward. Understanding the role of fathers would also help challenge assumptions that mothers are the most important causal factor shaping their children’s health. This could help lessen the blame sometimes placed on mothers for the ill health of the next generation.

What’s the current evidence like?

In the paper, we reviewed all the current literature we could find on paternal effects on offspring risk of obesity and type 2 diabetes. We found that, although there have been about 116 studies, this is far less than the number of studies looking at maternal effects. Also, a lot of these studies just show correlations between paternal factors and offspring health (and correlation does not equal causation!).

What is needed now is a concerted effort to find out how much paternal factors actually causally affect offspring health. This is exactly what EPoCH is trying to do, so watch this space!

This content was reposted with permission from the EPOCH blog.

Teens who hit puberty later could face bone health issues later in life, studies suggest


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Ahmed Elhakeem, University of Bristol

Puberty is a time of dramatic development for both boys and girls. Not only are those hormones raging, but there’s all the bodily changes to contend with.

Puberty is driven by the activity of sex hormones and its onset is announced by the appearance of pubic hair, beards and breasts. Along with the dramatic hormone-driven changes to a child’s body, another defining features of puberty is the adolescent growth spurt – children become taller and eventually physically mature into adults.

For boys and girls this growth spurt generally happens at different ages. And there can be big differences as to when the growth spurt happens. For girls, rapid growth generally occurs around age eleven and a half years but can begin as early as eight or as late as 14 while for boys it generally happens a year or two later than girls. Children continue to get taller during their growth spurt until the ends of their long bones fuse and stop increasing in length, which happens around the end of puberty.

Children’s bones develop rapidly during puberty. And our new findings published in JAMA Network Open suggest that teens who have their pubertal growth spurt later could have more problems with their bone health in the future. In essence our research shows that the timing of puberty might influence or at least signal a child’s bone strength throughout adolescence and into early adulthood.

Weak bones

Our study is not the first to report a link between the timing of puberty and bone strength. A 2016 study of British people born in 1946 showed that children who had their growth spurt at an older age had lower bone density near the end of their forearm bone when measured decades later in old age, making them more likely to get a broken wrist.

More recently, a study of adolescents and young adults from Philadelphia showed that people who were genetically predisposed to later puberty had lower bone density at the spine and hips sites which are known to be susceptible to osteoporosis in later life. This is an ageing-related condition where bones lose their strength and become more likely to break.

Our study tracked the development of bone strength in a group of British children through to adulthood and found that teens who hit puberty at an older age tend to have lower bone mineral density which is a strong indicator of having weaker bones. We found that this continued to be the case for up to several years of their adult life.

Measuring puberty

We analysed data from more than 6000 children from the Children of the 90s study. This is a multi-generational study that has tracked the lives of a large group of people born in the early 90s around Bristol in the south west of England.

Children whose genetic makeup triggers a later-than-average start to puberty are at increased risk of having weaker bones as adults.
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We made use of multiple bone density scans taken from each child to assess their bone strength across a 15-year period between the ages of ten and 25 years.

To calculate the age when the children went through puberty, we tracked each child’s height and used this information to estimate the age when each child went through the adolescent growth spurt. We then assumed that children that had their growth spurt at an older age must have started puberty later. As a check, we repeated our analysis in girls using the age they reported getting their first period as a different indicator of when they hit puberty and we came to the same conclusions.

Rebuilding bone density

Our research adds to the growing evidence that children who mature later may be at increased risk of breaking a bone as they grow and mature. And that they may also have an increased risk of getting osteoporosis later in life.

Of course, there are things people can do to strengthen their bones. But given our findings, it is clear there is now a need for bigger and more detailed studies into the very complex relationships between puberty, growth and bone development. Continuing to track the lives of the people in our study will be crucial if we are to discover how puberty might impact people’s bones as they go through adult life and eventually move into old age. This will help to further understand the causes of osteoporosis and ultimately help people to maintain healthy bones throughout their lives.The Conversation

Ahmed Elhakeem, Epidemiologist, University of Bristol

This article is republished from The Conversation under a Creative Commons license. Read the original article.