30+ year cohort population study finds 'rapid nutrition transition' among Brazilian infants

22-May-2019 - Last updated on 22-May-2019 at 13:21 GMT

Undernutrition among children in the Brazilian city Pelotas has dropped over the past three decades but obesity has rapidly risen, a shift that presents new challenges to public health in Brazil, say researchers.

Writing in the International Journal of Epidemiology, researchers from the Federal University of Pelotas and Catholic University of Pelotas in Brazil published findings from four population-based birth cohorts in Pelotas between 1982 – 2015. Each study included over 4,200 births and children were measured at approximately 12 months in 1982, 1993, 2004 and 2015.

'Overweight has replaced stunting'

Findings showed the prevalence of stunting declined 53% over the period, from 8.3% in 1982 down to 3.9% in 2015, while wasting prevalence remained stable and at low levels under 2%. However, the cohort study showed overweight prevalence increased by 88%, with a “particularly fast upsurge after 2004”, rising from 6.5% in 1982 to 12.2% in 2015.

“Our results confirm the rapid nutrition transition in Brazil, with marked reduction in levels and inequalities in undernutrition in parallel with a rapid increase in overweight, which became the main nutritional problem for children,” the researchers wrote.

Results suggested children in Pelotas were not facing a double burden of malnutrition, rather that “overweight has replaced stunting” at population level.

“Our comparison of the four cohorts showed marked improvements in undernutrition over a 33-year period, with concomitant reductions in socioeconomic and, to a lesser extent, in ethnic inequalities. Overweight prevalence, on the other hand, increased markedly, particularly among the poor,” the researchers said.

“The nutrition transition is bringing new challenges to public health in Brazil.”

A cause for concern

The researchers said both undernutrition and overweight in early life were “important risk factors for a number of conditions along the life course”.

Undernutrition in early life had “well-known, short-term consequences”, they said, particularly related to higher severity and mortality of infectious disease, and it also carried long-term impacts regarding height, reproductive capacity, intelligence and productivity.

But it was the transition away from undernutrition towards overweight that was concerning, they wrote.

“In light of Brazil's success in reducing undernutrition, the main nutritional challenge presented by its children is that of overweight. Childhood body mass index (BMI) – particularly at the age of two years or later – tends to track over the life course, with well-described consequences regarding the risk of non-communicable diseases. Our report of a prevalence of 12.2% among 12-month-old children in 2015 is higher than that of 7.4% estimated for Latin America under-five children.”

The researchers said data from national surveys up to 2007 “failed to detect” the recent upsurge in 2004 of overweight infants in their cohort study.

Understanding the rise in childhood obesity

Childhood overweight and obesity, the researchers said, was of increasing concern given it was a “strong predictor of excessive weight and of cardiovascular and metabolic diseases later in life” and so it would be important to understand what was driving this rise, particularly at such a young age.

“In view of the inverse association between breastfeeding and child obesity, it will be important to understand the rise in overweight during a period of time when breastfeeding rates have shown substantial increase,” they wrote.

The four cohorts received funding from a number of agencies, including the World Health Organization (WHO), European Union, Brazilian National Council for Scientific and Technological Development (CNPq) and the International Development Research Center, among others.

The researchers said that despite some limitations to the analyses, strengths of the studies included that they were population-based, had a prospective design, had high rates of follow-up and used comparable methodology by the same research team over time, except for 1993 when there was hyperinflation in Brazil.

Source: International Journal of Epidemiology
Published: April 2019, Volume 48, Issue Supplement_1, Pages i80-i88. Doi: 10.1093/ije/dyy233
Title: “Infant nutrition and growth: trends and inequalities in four population-based birth cohorts in Pelotas, Brazil, 1982-2015”
Authors: Helen Gonçalves et al.