Social imbalance in affluent nations is rising while in parts of the emerging world many diseases are waning, Margaret Chan, head of the World Health Organization said on Monday.
"In some wealthy countries, the difference in the quality of life between the older generation and today's youth is the greatest ever recorded," said the WHO director general, speaking at the opening of the body's board meeting.
"Last year was a time when many countries realised they were losing their middle classes, the very foundation of democracy and economic productivity," she said, urging that a commitment to public health must be sustained.
In a text version of her speech Chan cited a recent Organization for Economic Cooperation and Development report showing income inequality in wealthy nations has reached the worst levels in nearly 25 years.
"That report further concluded that societies with the least inequality had the best health outcomes, regardless of the levels of spending on health," Chan said, noting, "money alone does not buy better health."
She stated: "Those who suffer or who benefit least deserve help from those who benefit most," but this is not what happened last year, particularly in well-off nations, according to numerous reports.
In large parts of the developing world vast inequalities in access to health care also exist, she explained.
"But misery, for many groups, for many diseases, is actually going down. Those who benefit least are getting help from those who benefit most," said Chan.
She noted that in the first decade of the 21st century, HIV/AIDS and tuberculosis epidemics peaked, beginning a slow decline along with a turn around in a deteriorating malaria situation.
"Young child mortality dropped below 10 million for the first time in nearly six decades. Compared with 12 million under-five deaths in 1990, the figure for 2010 was 7.6 million, a drop of more than 40 percent."
Chan said that in sub-Saharan Africa the fall in the under-five mortality rate was accelerating at double the rate it had shown between 1990 and 2000.
Maternal deaths worldwide, "the starkest statistic in public health," have also begun to fall, she said.
In addition, "In 2009 alone, an estimated 800 million people received preventive chemotherapy for at least one of the neglected tropical diseases."