Do you know your birth weight? I think this question might not be easy to answer if you have not been told by your parents or have your postnatal or weighing card. Did you ever sight your postnatal or weighing card when you were young?
Give your mum or your dad a call or make a visit to find out if they are available. I only hope they have the record or can remember to tell you. Why has this become necessary? It may help you assess your risk of kidney disease now or later in life. Yes, low birthweight has been shown to be associated with the development of chronic kidney disease in a lot of studies.
The causes of chronic kidney disease are unknown in most cases in sub-Saharan Africa and in Ghana. This is because patients present too late for thorough investigations to ascertain the cause of the chronic kidney disease. The majority of cases of chronic kidney disease in Ghana are believed to be caused by some inflammation in the kidneys with varied risk factors. Globally, majority of chronic kidney disease seen is due to diabetes mellitus followed by hypertension. However, in Ghana, most patients present without diabetes and have hypertension at very young ages so the belief is that they may have developed the hypertension as a result of kidney disease and not the hypertension causing the kidney disease.
What then accounts for the majority of cases of kidney disease in sub-Saharan Africa and for that matter Ghana? It is still not certain and under investigations to ascertain both the hereditary and environmental factors associated with the increased prevalence of chronic kidney disease in sub-Saharan Africa.
There is a strong hypothesis to suggest that people who are born prematurely before their estimated date of delivery or born at nine months but with low birth weight, are at increased risk of kidney disease in the long term. This hypothesis by Barker and Brenner seeks to explain that at preterm delivery, babies have less number of the cells that make up the functional unit of the kidneys called the nephrons. This can be decreased by 20 to 50 per cent in babies with low birth weight. In effect they do not have the full set of the functional units required for optimum function of their kidneys.
Every normal kidney is expected to have about one million functional units in each kidney. With less than one million functional units in each of the kidneys due to underdevelopment, the kidneys are likely to decrease further and quicker with time. This will cause the person with low birth weight to lose a significant amount of the kidneys’ functions at a relatively younger age than the general population and therefore lead to kidney disease. It has been shown that a decrease in the number of functional units to compensate for the functional units left and with time this leads to increased pressure in the kidneys. This increased pressure eventually leads to the passage of protein in the urine that destroys the sieving ability of the kidneys in the process of compensation.
The passage of protein in the urine with time is detrimental to the kidneys and will therefore lead to kidney damage with time. The pressure in the kidneys also leads to high blood pressure (hypertension) in some cases and this high blood pressure can also cause more kidney damage with time. With that explanation, it has been suggested that low birth weight is associated with increased risk of chronic kidney diseases. I personally believe this may account also for the increasing risk of kidney disease among the poor, malnourished, black population and people in sub-Saharan Africa.
Let’s now clearly define the terms and assess clearly our risk of kidney disease if we know our birth weight. Low birth weight is defined by the World Health Organization as birth weight of an infant of less than 2.5kg regardless of duration of baby in the mother’s womb. Preterm or babies born in less than 37 weeks in the womb, are particularly at risk of low birth weight. Globally prematurity is currently the leading cause of death among children under five years and the leading cause of disability and ill-health later in life including the risk of conditions such as hypertension, diabetes, obesity and kidney disease. It is estimated that over 15 million babies are born too early every year worldwide.
Unfortunately, over 60 per cent of these preterm born are from sub-Saharan Africa including Ghana. In Ghana, 128,000 babies are born too soon each year and 8,400 children under five die due to direct preterm complications and the rest have an increased risk of diabetes, hypertension and kidney disease. Diabetes and hypertension can also cause chronic kidney disease.
Factors that increase one’s risk of low birth weight include race, age of mother less than 15 years, twin delivery, mothers with poor health or mothers who take alcohol and illicit drugs, and mothers with poor socioeconomic status all contribute to low birth weight. Mothers have a responsibility to decrease their children’s risk of kidney disease by modifying some of the factors above if possible.
How can one then prevent chronic kidney disease with this knowledge?
- Let’s prevent low birth weight as much as possible. Antenatal care (ANC) is a key factor in preventing preterm births and low birthweight babies. At prenatal visits, the health of both mother and fetus can be checked. Healthy eating habits are advised to enable baby gain the proper amount of weight in pregnancy. Mothers should also avoid alcohol, cigarettes, and illicit drugs, which can contribute to poor fetal growth, among other complications.
- Fathers have a responsibility to also support their wives during pregnancy to ensure delivery of babies with good birth weight.
- Know your birth weight if you can – it’s time to pay your mum or dad a visit to know your birth weight. Don’t stress your parents if they do not know. Just ensure you take care of your kidneys well if you do not know. You can help your children by preventing them also from developing low birth weight.
- Screening to assess your risk of kidney disease if you are known to have had low birthweight with regular follow-ups to prevent hypertension and kidney disease.
- Regular monitoring of your kidney function to see if there is protein and see your doctor if there is.
- Seek the help of a nephrologist if you are found to have kidney disease to prevent progression to kidney failure.
By Dr. Elliot Koranteng Tannor