Some occupations are more risky and creates so many health problems. Some industries are clinked with various diseases. Death rate in some occupations is high while low in others. For example; death rate is high in workers who are working in the mines and chemical industries. Occupation provides income and standard of living which influence death rate.
Biological factors include age of the mother, order of birth, time interval between births etc. it has been observed that fetus and post-natal mortality rates are high at the young age of the mother like below 19 for the first birth order up to the age of 29, these rates decline and then increase after it. The maturity of an infant is also an important factor.
There were several factors (Famines and food shortage, Epidemics, War and Terror etc) have led to high mortality rates up to 19th century. However after the agricultural and industrial revolutions, mortality rates have fallen everywhere. Following were the most important factors for the decline of the mortality rate. Agricultural revolution started in England around 1700 AD and spread throughout Europe and the European settlements in the world.
Population change has been defined in terms of mortality, fertility and migration. According to the United Nations, mortality is the percentage of death in the population. Death has been defined by WHO, death is the permanent disappearance of all evidence of life at any time after birth has taken place. This definition proves that death can occur only after live birth.