Undernutrition and Vitamin A Deficiency in Mali
every three for food intake inquiries and health status assess-
ment (planned n ϭ 500) and from this later group one out of
every two individuals for biochemical status assessment
vitamin A and carotenoid were consumed during the previous
week. Trained local health practitioners compiled a list of 21
available foods, six from animal origin rich in retinol and 15 of
vegetable origin rich in beta-carotene. Sauces containing veg-
etables rich in beta-carotene, such as baobab or gombo leaves,
which are ingested in very small amounts, were given a weight
considered to one fifth of a serving in the intake analysis.
Morbidity. Two weeks’ history of morbidity symptoms
was recorded: episodes of coughing, fever, diarrhea as well as
oral intake of rehydration salts. A six-week history of measles
and measles immunization and use of vitamin A capsules for
the preceding three months were noted.
(planned n ϭ 250).
Measurements
Ophthalmologic Examination. A history of night blind-
ness (XN stage) was obtained by questioning children’s moth-
ers. Three questions were sequentially asked to ascertain if the
child was able to see during daytime, during the night and,
finally, if night blindness was present using a vernacular term
(in Dogon “gire nama”, in Peul, “pinku” and in Bambara
“
surofinye”). Children who also had daytime vision problems
Biochemical Markers. Vitamin A status was assessed by
measuring serum retinol concentration and the Modified Rel-
ative Dose Response test (MRDR), an individual indicator of
liver retinal stores [10,11].
were excluded.
All children received an ophthalmologic examination by the
same ophthalmologist using a X2.5 magnification with a lamp.
Clinical signs of xerophthalmia, Bitot spots (X1B) and active or
non-active corneal lesions were noted. A categorical variable
for xerophthalmia was derived corresponding to the presence of
night blindness and/or Bitot spots.
Vitamin A treatment (one capsule of 200 000 IU ϫ 3) was
given to children showing clinical signs of vitamin A defi-
ciency and tetracycline ointment was applied in case of ocular
infection.
Briefly, 200 g of acetate of 3,4-dehydroretinol (DR) was
orally administered. Five hours later, 0.5 mL of capillary blood
was extracted by pricking the child’s finger with a vaccination
scratch blade and was collected in a “Microtainer Benson
Dickson” tube. The tubes were set in a vacuum flask filled with
ice and kept dark. Within three hours the tubes were centri-
fuged at room temperature (1300 ϫ g, 10 min). The serum was
fractionated off, aliquots placed on ice for no more than five
hours, frozen to Ϫ20°C in a deep-freeze at the nearest health
center before being taken to Bamako and then shipped on dry
ice for laboratory analysis to Grenoble (France). Freezer tubes
were thawed slowly to room temperature just before assay. A
high performance liquid chromatography assay (HPLC), made
up of an isocratic system using silica gel (adsorption) as the
stationary phase, was used for dehydroretinol and retinol de-
termination, and 0.5 mL aliquots of serum were extracted.
Briefly, proteins were precipitated with absolute ethanol, and
the fat-soluble vitamin A was extracted subsequently into an
n-hexane phase, and analyzed by automated high-performance
liquid chromatography with a Lichrosorb Si 60.5 column. Ret-
inol peak was detected spectrophotometrically at 313 nm. The
peaks were integrated by means of Perkin Elmer Chromatog-
raphy Data Station Sigma 10B system. Cumulative quality-
control data for each analysis were provided during the analysis
period. Briefly, the coefficients of variation for the estimation
of retinol and dehydro-retinol were 3.3% and 3.0%, respec-
tively.
Anthropometry. Stature (cm) and body weight (kg) were
measured by one of the two trained nurses. Infants under two
years of age were weighed using a 25 kg Salter hanging scales
(CMS Weighing equipment, High Holborn, London, United
Kingdom). Children over two years were weighed on scales
calibrated before each session. Body weight was measured on
children fully dressed (with light clothing) but without shoes.
Infants under two years were measured lying down using a
conventional wooden height board. Individuals over two years
were measured standing up.
Whenever possible, age was verified on presentation of a
birth certificate. Otherwise, it was estimated using a local
calendar and history of past events.
These measurements allowed calculation of three standard
normal deviate (Z) scores based on reference values from the
National Center for Health Statistics (NCHS) published by
WHO [8]:
•
(
•
the weight for age (W:A), reflecting weight insufficiency
underweight)
the height for age (H:A), reflecting stunted growth or
The ratio of DR to retinol was calculated. The performance
and reproducibility of this ratio of has been evaluated in dif-
ferent groups with normal and abnormal vitamin A classified
status [11,12]. A deficiency is defined as a ratio greater than or
equal to 0.06. A prevalence of abnormal tests greater than 20%
defines a public health problem. The situation is considered to
be severe when the prevalence is over 30% [12]. Serum retinol
thresholds used were 0.7 mol/L and 0.35 mol/L, reflecting
low status and severe deficiency, respectively.
chronic malnutrition,
the weight for height (W:H), reflecting wasting malnutri-
tion.
•
Z-scores under the threshold of Ϫ2 were considered as mod-
erate and those less than Ϫ3 as severe nutritional deficiency.
Food Survey. Information about breastfeeding and age for
weaning was recorded by questioning the mothers. A seven-day
food frequency questionnaire was administered to them to
estimate the number of occurrences on which food sources of
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