Growth in human is considered of having a set pattern with a rapid decrease in height velocity in initial 2 to 3 years which is followed by a further decrease during pubertal growth and later on a final decrease to zero growth when the growth plates are fused. Catch-up growth is a phenomenon wherein there is an increase in velocity of height during the period followed by a period of inhibited or slow growth, particularly after a period of nutrient deprivation.
Catch-up growth is defined as height velocity above the statistical limits of +/-2 SD of the mean for age. The main purpose of catch-up growth is to bring the child again back on the original growth curve which has been inhibited due to growth retardation.
Compensatory Growth & Catch-up growth
Compensatory growth and catch-up growth are two different phenomena which are mostly used as synonyms. Compensatory growth is a term used to describe the growth of an organ or any part of the organ but not of the whole organism. It is the growth which occurs after loss of the actual mass of a tissue and is characterized by a feedback mechanism of physical mass or physiological load. Whereas, catch-up growth is the rapid growth that occurs and reimburses for the loss that occurs in the tissue which is not associated with the simple feedback mechanism.
Pattern of Catch-up Growth
There are two different temporal patterns of catch-up growth. The first pattern, where individual features increased and accelerated growth with a reduction in the deficit of the retarded growth in few years. The child who is retarded will improve the percentile and achieve the adult height. The second pattern is where the child remains in the low percentile stage for many years and continue to grow at a normal velocity for the age of bone or chronological age. The drawback with this pattern is that the bone maturation is delayed as the growth is continued beyond the actual age so that the percentile of the height is improved. Thus, in this case, once the child is stunted, he/she will remain stunted. Stunted child means the child has the short height for the age. Stunting refers to linear growth retardation which results from chronic malnutrition. This might begin during pregnancy in a foetus and continue during infancy and childhood.
An individual who faces growth retardation and later on catch-up growth will attain adult height but the growth will still be incomplete as the normal adult height will not be achieved, which would have been achieved when there is no impairment of growth.
The child’s height can be reversed but if the environment of child’s growth is improved through improved nutrition and following proper health interventions. However, this should happen in first few years of life, as it is well known that stunting is irreversible when the child crosses his second birthday. The stunted child will have many other consequences which are affected during his life cycle. The consequences include undernutrition, reduced immune function, reduced cognitive development, reduced achievement in the school, increased absenteeism, reduction in the economic productivity and thus less potential to earn income, the standard of living is affected and thus the quality of life. Also, there is an increase in the mortality rate and these children are at increased risk of developing many chronic diseases and infections.
Prevention of Catch-up growth
Catch-up growth can be achieved when the child who is affected by growth retardation has been provided with proper nutrition, health, and care.
The child should be given nutritious food with all five food groups that are cereals, pulses and legumes, vegetables, fruits, milk, oil and fat and non-vegetarian foods. Health care is also essential, the child should receive all the immunization on time and treatment of any illness to be taken care of immediately. The environment in which the child is living should be proper with proper hygiene maintained in the home and also the surrounding area. As if the hygiene and cleanliness are not maintained there is increased the risk of illness and infection and might affect the child’s health.
Thus, proper care and nutrition can help in achieving the complete catch-up growth and bring the child back to the normal growth curve. The change in height-for-age z-scores can depict the status of the child’s height and compare it to the standard height of the child as per the age of the child.