Children in urban areas are usually larger than children in the surrounding rural areas. Indeed the tendency towards greater size and more rapid maturation in Europe in the last hundred years has been held to be a consequence of urbanization. By urbanization we do not mean simply a high population density, other features such as a regular supply of goods, health and sanitation services, large medical institutions, educational, recreational and welfare facilities must be present. A European or North American city is considerably different from urbanized area in Africa or even a city in India or Japan.
Data from European countries on height and weight from Finland, Greece and Rumania also shows that children in the cities are larger than those in rural areas, but the amount by which urban children were taller and heavier varied. Eight year old boys in Helsinki, for example, were 2.4 cm taller and 1.6 Kg heavier than rural Finnish boys, while in Greece the urban-rural differences were twice as great. During puberty the differences became greater, presumably because of the earlier appearance of the adolescent spurt in city children. While part of urban-rural differences results from earlier maturation. In developing countries also the same trend is being witnessed, urban children being taller and getting matured earlier than the rural children. Better off children, that is children who live in parts of towns that are nearer to urban areas are considerably taller and heavier than the rural children.
In every urban-rural comparison so far reported urban girls have an earlier menarche than rural girls. As with growth in body size, age at menarche is closely related to the health and nutritional level of an individual or a population. In a study from Bombay even urban slum children have been reported larger than children in the corresponding rural areas where even the poor were said to have received more food in the first two years after birth than children in rural areas.
Many studies conducted in India on growth of rural-urban children also show better overall growth and earlier maturity among urban children than their rural counterparts.