Early environmental and biological impacts on lifelong health Flashcards
LO:
- Embryo-fetal environment: Summarise how the extrauterine environment can impact embryo and fetal development and health across the life-course.
- Child and adoslescent development: Summarise the key developmental milestones of child and adolescent development and expected timeframes.
Developmental origins of health and disease: Concept Mechanisms & Evolutionary Implications
Critical Periods
There are believed to be critical periods of development for certain capabilities. Lenneberg popularised the hypothesis of critical periods in 1967 based on the acquisition of a first language, with the critical period starting at birth and ending in early adolescence. During this time, the brain is particularly sensitive to certain stimuli and experiences which are necessary for the development of specific neuronal pathways. Repetitive use of these pathways is very important in order to maintain and strengthen the connections. Another example of critical periods is shown by Hubel and Wiesel (1964). In their investigations, kittens that were artificially blinded during a critical period were never able to see, even when the blinding was reversed. For children with profound sensorineural hearing loss, small electrical devices called cochlear implants can improve hearing and allow children to perceive and use spoken language. A number of studies have shown that the earlier a device is placed, the better the hearing and language outcomes. When there has not been a long period of auditory deficit, a child’s hearing and communication levels are comparable to their normal hearing peers, but delayed placement of a cochlear implant can lead to impaired language development. This is also true of other types of hearing aids.
Challenges foetus might face in utero that might have lasting impact on its health:
- cortisol exposure-stress on mothers can have a big impact
- Smoking (grandparents smoking can affect grandchildren)
- Mineral deficiencies-rickets is coming back
- alcohol
- packaging disorders such as developmental dysplasia of the hip eg breech position, clubbed foot
- teratogenic medication
- Infection
- Environmental factors
Long term health and risk of disease: can think of nature and nurture effects
Epigenetics-whether genes are switched on or off
External influences can shape a child’s development:
Babies are extremely reactive to the social interaction that surrounds them
eg Stillface experiment-Mother first interacts with baby and baby is happy and then mother stops responding and interacting with the baby and the baby does everything to try and get the mother’s attention back and the baby starts getting extremely stressed and crying and displays negative emotions.
1989 Romania opened up after Romanian revolution, children went to orphanages and were not touched or interacted with and they had smaller brains and didn’t catch up, better chance if adopted before age 2.
Barker hypothesis
-Drugs and alcohol can have direct effect on baby when born but Barker looked at effect uterine environment on how you are as an adult, which may not be seen immediately when born.
Impactful article: Trajectories of Growth among Children Who Have Coronary Events as Adults
Note-these are association studies so won’t definitely get disease, and there are many other risk factors for cardiovascular disease.
It looked at adults who had MI and stroke. A lot of adults had been small as babies, but thereafter they put on weight. It wasn’t so much weight at certain time points but it was the rate that you gain weight that puts you at risk of going on to have coronary event.
Centile chart-weight is a normal distribution bell shaped curve and within this is normal
centiles run from o.4 to 99.6
eg child plotted at birth on 25th centile and we go on to track their weight. Most kids will stay around this centile. Obviously they won’t follow this line completely but they will stay within range. But what was found in this study was that with these children they were born small and stayed like this for toddler years but at around age 9 their weight shot up centile chart. Small children with rapid weight gain were found later as adults to have increased risk of coronary effect but if child was already at high centile this wasnt the case.
Barker hypothesis
Metabolic syndrome-high BP, type 2 diabetes, high cholesterol, obesity
Why would a small child be at risk of this?
Top diagram-mum getting adequate nutrition so foetus grows to its optimum size, whatever is normal for that Mum eg 99 centile, 25 centile, whatever its optimum is. As long as child has adequate nutrition it will become a normal sized adult.
Bottom pic-for some reason Mum has malnutrition eg not eating enough or placental issues or pre-eclampsia so not enough nutrients reaching baby, so baby is inutero growth restricted (IUGR). So don’t reach optimum weight in foetus. This baby has been programmed in utero to believe that it is in an environment of low energy so it needs to take whatever it gets. This programme is thought to be long term so when baby is born into a high energy environment, that child will rapidly put on weight so as an adult they become larger putting them at risk of metabloic syndrome.
This is due to epigenetic changes. So this child might have more of its genes turned on more so it will do everything it can to get more food and so will be more likely to put on weight.
Early life origins concept
shows how epigenetic changes can have an effect on the way that maternal genes are expressed eg way that blood vessels develop so may be at risk of hypertension, growth restrictions may mean kidneys are smaller, how immune system develops so may be at risk of allergy.
This early life orgins has been associated with the following diseases:
Tracking patterns and influences on health across generations using genograms:
Task: Genogram
Task: Taking a 3 Generation History and Creating a Genogram
Note: cousins will be on same line as you because they are the same generation.
Genograms show information that can be used to evaluate an indivdual’s health risks based on family history (and shared environment), and can be annotated with further relevant information according to the clinical context. Genograms are used routinely in some specialties (eg clinical genetics or haematology) wherin they can be used to record which members of a patient’s family carry a particular gene or suffer from an expressed inherited disorder.
In specialties like paediatrics they are usually taken in order to gain a more informed understanding of a patient’s personal circumstances and the background to their presentations.
These are the basic symbols used in a genogram:
Drawing a Genogram
Our environment
NHS healthy child programme-available to everyone
NHS healthy child programme
Implicated mainly by midwives and community work
Obese children will become obese adults and this can increase MSK problems as well as cardiovascular risk. So this needs to be corrected as early as possible.
Family centres to help support care givers. By supporting parents and their mental health and well being you will have healthier children.
Immunisation is one of the most important parts of this programme
Identify high risk families and give them additional tailor-made support eg if caregiver has disability and needs extra help, or large families or single parent families or families struggling with substance abuse etc.
Heel prick test: The blood spot test screens for the following 9 rare but serious conditions.
- sickle cell disease
- Cystic fibrosis
- Congenital hypothyroidism
- Inherited metabolic diseases:
- phenylketonuria (PKU)
- medium-chain acyl-CoA dehydrogenase deficiency (MCADD)
- maple syrup urine disease (MSUD)
- isovaleric acidaemia (IVA)
- glutaric aciduria type 1 (GA1)
- homocystinuria (pyridoxine unresponsive) (HCU)
Height, weight, eyesight, hearing
Fundamentals of a good screening test:
- Good sensitivity and specificity
- High frequency
- Treatable condition, otherwise pointless to screen for
- Minimal/non-invasive
- Identidied early and before a critical point, so can start supplementing early to avoid the onset of symptoms
- Should have big effect eg reduce morbidity and mortality
- Cost effective
UK Perinatal Screening Programme
Below is a summary of the screening programme offered to all pregnant women and infants in the UK
How much screening happens during pregnancy and first few weeks after baby is born
Early pregnancy-screening for genetic disease eg bloods taken and screened for haemoglobinopathies eg SCC
Women who are high risk are detected so they can get more care
First scan-start thinking about trisomies and are given risks based on scans especially 21, but also 13 and 18
All optional
NIPT test-not on NHS YET… screen for genetic disease from foetal blood
Screen for gestational diabetes and preeclampsia (BP and protein in urine)
As baby is born-screened
24hrs-all babies get baby check-eyes, heart, hip dysplasia, spine, hearing test done
5-7 days have newborn blood spot, done a few days later as otherwise if done as soon as born will still have mother’s thyroxine in blood.
Newborn physical exam repeated again at 6-8 weeks to check for anything that was missed.
Sure start-interventions that can be done
As prevention is cheaper than treatment
Summary: Long term health and risk of disease
