Human growth

The study of human growth is known as auxology. Growth and height have long been recognized as a measure of the health and wellness of individuals, hence part of the reasoning for use of growth charts. For individuals growth trends are tracked for significant deviations and growth is also monitored for significant deficiency from genetic expectations. Genetics is a major factor in determining the height of individuals. However, it is far less influential in regard to populations. Average height is increasingly used as a measure of the health and wellness, standard of living, and quality of life of populations. Attributed as a significant reason for the trend of increasing height in parts of Europe is the egalitarian populations. There, proper medical care and adequate nutrition are relatively equally distributed. Changes in diet or nutrition and a general rise in quality of health care and standard of living are the cited factors in the Asian populations. Average height in the United States has remained essentially stagnant since the 1950. Severe malnutrition is known to cause stunted growth in North Korean, portions of African, certain historical European, and some other populations. Diet, especially such things as junk food provoke health problems such as obesity. Exercise, fitness, pollution exposure, sleep patterns, climate, and even happiness or psychological well-being are other factors that can affect growth and final height. Height is determined by the complex interactive combination of both genetics and environment. Genetic potential plus nutrition minus stressors is a basic formula for human growth. Humans grow fastest as infants and toddlers, and then during the pubertal growth spurt. A slower steady growth velocity occurs throughout childhood between these periods. Some slow, steady, declining growth after the pubertal growth spurt levels off is common for most of the people. These are also critical periods where stressors such as malnutrition, or even severe child neglect, have the greatest effect. Conversely, if conditions are optimal then growth potential is maximized. In addition, there is catch-up growth, which can be significant for those experiencing poor conditions when those conditions improve. Moreover, the health of a mother throughout her life, especially during her critical periods, and of course during pregnancy, has a role for growth and human tallness in future. A healthier child and adult develops a body that is better able to provide ideal and optimal prenatal conditions. The pregnant mother’s health is important as gestation is itself a critical period for an embryo and fetus. Some problems affecting height during this period are resolved by catch-up growth assuming childhood conditions. Moreover, there is an accumulative generation effect such that nutrition and health over generations influences the height of descendants to varying degrees. The precise relationship between genetics and environment and exact role of genetics itself is complex and uncertain. Human height is both of moderately high phenotypic plasticity and is highly heritable since height is a multigenic trait. There are substantial relationships in the heights among biological families. The heights of parents and family are a good predictor for the height of their children. Environmental influences are most pronounced if they are highly favorable or unfavorable to growth. That is especially when environmental influence occurring during critical periods and when continuing multigenerationally. Genetic profile or genotype provides potentialities or proclivities, which interact with environmental factors throughout the period of growth resulting in phenotype in final adult height. Essentially, the developing body devotes energy to growth after other bodily functions are completely satisfied. Asian populations were once thought to be inherently shorter, but with the increases in height in East Asian nations such as China and South Korea as diet changes, it now seems that humans as a species probably possess a roughly similar genetic height potential. It seems that thus a predictive genotypic basis for height differentiation has not yet evolved.