The empowerment of women and the reach of NGOs have contributed to Bangladesh's remarkable success in healthcare, which has included significant improvements in the survival of under-fives, immunisation coverage and tuberculosis control, according to the Lancet.

The achievements are in spite of low spending on healthcare, a weak health system and widespread poverty. Bangladesh's health success has come despite its low gross domestic product of $101.9bn. The nation of 153 million people ranks in the lowest income group of countries, on a par with neighbours Nepal and Cambodia.

Yet, Bangladesh's life expectancy is superior to that of other countries in the region, except Nepal. Bangladesh's infant mortality, under-fives mortality and maternal mortality rates are also better than other countries in the region. Bangladesh is ahead of Pakistan in all education and health indicators. But there are caveats. Despite improved survival rates, nearly half of children in the country have chronic malnutrition, a problem shared with India, which also has a high prevalence of child and maternal malnutrition.

"Over the past 40 years, Bangladesh has outperformed its Asian neighbours, convincingly defying the expert view that reducing poverty and increasing health resources are the key drivers of better population health," said the report's co-leader, Professor Mushtaque Chowdhury, from Brac, a Bangladeshi NGO. "Since 1980 maternal mortality has dropped by 75%, while infant mortality has more than halved since 1990, and life expectancy has increased to 68.3 years – surpassing neighbouring India and Pakistan."

Progress in infant, child and maternal mortality has been particularly striking, with an unprecedented reversal in the number of deaths among girls compared with boys. Maternal mortality was reduced from 574 deaths per 100,000 livebirths in 1991 to 194 deaths in 2010.

Tuberculosis treatment is another success. Through mass deployment of community health workers, the number of people cured rose from less than 50% to more than 90% – among the highest in the world. Another is contraceptive use. By recruiting female health workers to deliver door-to-door family planning services, Bangladesh has achieved high (62%) contraceptive prevalence and a dramatic fall in birth rates, from an average 6.3 births per woman in 1971 to 2.3 in 2010 – a rate unparalleled in other countries with similar levels of development.

Not all health indicators are positive, particularly child malnutrition. The rates of underweight in children from the poorest families fell from 59% in 2004 to 50% in 2010. Even in the wealthiest quintile, 21% of children were underweight in 2010.

The data underlines the complexity of malnutrition, where factors range from poverty and hunger, low rates of breastfeeding, inadequate care and complementary feeding, and recurrent infections. Paradoxically, there is a rising incidence of obesity, a phenomenon noted elsewhere in poorer countries, including China and India.

The Lancet attributes Bangladesh's success to a "pluralistic" health system pulling in government and NGOs that emphasised the role of women in delivering action on family planning, immunisation, oral rehydration therapy, tuberculosis and vitamin A supplementation. The role of gender equity, including the widespread education of girls, was noted in the report.

"Perhaps the most powerful strategy for health was the country's distinct acknowledgment and support of women to national development," said the report. "Educational policies that favoured girls caused near-universal primary education and removed gender disparity in educational access … women were brought to the forefront of development work as leaders, implementers and receivers of services."

The report cites the importance of NGOs such as Brac, Grameen and Bangladesh Diabetic Samity in contributing to the improved health of poor people in rural areas. "NGOs as a group have innovated to address issues of poverty, unemployment, health, education and the environment, and in many cases the government and NGOs have worked together to achieve a common goal," it said.

Opinion is mixed on the role of foreign aid, which was about 6% of GDP between 1970 and 1990, dropping to 2% in 2005. However, the Lancet notes that external assistance was helpful in funding NGOs, which attracted up to 18% of total aid commitment in 2003.

Looking ahead, the report said that despite annual economic growth of 6%, persistent poverty would continue to limit health progress. More than 30% of the population are classified as extremely poor, and inequality has widened. Corruption and political fragmentation – with politics dominated by two irreconcilable parties – pose particular challenges.

Rapid urbanisation, with about a third of city dwellers living in slums without basic infrastructure and social services, and changes to lifestyle are increasing the risk of non-communicable diseases, including cardiovascular and metabolic diseases such as diabetes and cancers. Climate change might increase the frequency, severity and effect of natural disasters, threatening the health and resilience of society.

"The Bangladesh health system has been shaped to address the first generation of poverty-linked infections, and nutritional and maternity-related diseases," the Lancet said. "But given the epidemiological transition, the health system will have to be adjusted to grapple with chronic non-communicable diseases. For the fragile and evolving Bangladesh health system, the global attention on universal health coverage has not been translated into substantive action."