The various regions of population in the United States will become increasingly different from one another in years to come, a study released yesterday by researchers at the Joint Center for Urban Studies of MIT and Harvard states.

Existing patterns in fertility, migration and the labor market will increase regionalization during the next decade and the new diversity will not be confined to the traditional sun-belt/frost-belt division, the study says.

The study, "Regional Diversity: Growth in the United States, 1960-1990," relies on early data from the 1980 Census, yet differs from the Census Bureau's projection of increased regional uniformity.

Gregory Jackson, the center's assistant director, said yesterday the center's study is a short-term projection, whereas the bureau released a long-term forecast.

Jackson added that the bureau made "reasonable long-term assumptions when it predicted that regional trends will necessarily converge toward a national average."

But this convergence will not be seen in the short term, the authors of "Regional Diversity" said.

New England is included in the study as one of the regions to experience increased growth because of its historically low wage level--which will attract business to the area--and its abundance of rural areas. The study predicts that rural populations will continue to increase over time, giving an advantage to both New England and the West North-Central United States.

"It will be impossible to view the country in nice, uniform trends anymore," Jackson said yesterday.