Context One key target of the United Nations Millennium Development goals is
to reduce the prevalence of underweight among children younger than 5 years
by half between 1990 and 2015.
Objective To estimate trends in childhood underweight by geographic regions of
Design, Setting, and Participants Time series study of prevalence of underweight, defined as weight 2
SDs below the mean weight for age of the National Center for Health Statistics
and World Health Organization (WHO) reference population. National prevalence
rates derived from the WHO Global Database on Child Growth and Malnutrition,
which includes data on approximately 31 million children younger than 5 years
who participated in 419 national nutritional surveys in 139 countries from
1965 through 2002.
Main Outcome Measures Linear mixed-effects modeling was used to estimate prevalence rates
and numbers of underweight children by region in 1990 and 2015 and to calculate
the changes (ie, increase or decrease) to these values between 1990 and 2015.
Results Worldwide, underweight prevalence was projected to decline from 26.5%
in 1990 to 17.6% in 2015, a change of –34% (95% confidence interval
[CI], –43% to –23%). In developed countries, the prevalence was
estimated to decrease from 1.6% to 0.9%, a change of –41% (95% CI, –92%
to 343%). In developing regions, the prevalence was forecasted to decline
from 30.2% to 19.3%, a change of –36% (95% CI, –45% to –26%).
In Africa, the prevalence of underweight was forecasted to increase from 24.0%
to 26.8%, a change of 12% (95% CI, 8%-16%). In Asia, the prevalence was estimated
to decrease from 35.1% to 18.5%, a change of –47% (95% CI, –58%
to –34%). Worldwide, the number of underweight children was projected
to decline from 163.8 million in 1990 to 113.4 million in 2015, a change of
−31% (95% CI, −40% to −20%). Numbers are projected to decrease
in all subregions except the subregions of sub-Saharan, Eastern, Middle, and
Western Africa, which are expected to experience substantial increases in
the number of underweight children.
Conclusions An overall improvement in the global situation is anticipated; however,
neither the world as a whole, nor the developing regions, are expected to
achieve the Millennium Development goals. This is largely due to the deteriorating
situation in Africa where all subregions, except Northern Africa, are expected
to fail to meet the goal.