Characteristics of the study population
In the LCs, the number of mother-infant pairs of 4-5 was small and varied between 7 and 22 pairs depending on the population size of each communities. Thus in each LC all mother-infant pairs that met the inclusion criteria were recruited. Only two cases of refusal were recorded and this was due to the absence of the heads of household who had to agree to participate in the study. A total of 143 mother-child pairs were involved in the study. Of these, 2 did not complete the collection of saliva samples in the field and 1 had physiologically unacceptable data after enrichment measurements. Thus, 140 pairs had complete data and were retained for the overall analysis (Figure 1). Data on mother-infant pair’s households are presented in Table 1. The results showed that in the NEP area all heads of household were male, while in the non-NEP area there were 4.5% female heads, with no difference between the two areas. The average number of children under 5 years of age was comparable between the two areas. Both areas had the same socio-economic characteristics, with more than 50% of households in the middle and low categories. Food insecurity affected 38% and 37% of households in the NEP and non-NEP areas, respectively. There were no significant differences in socio-economic and food characteristics between the two areas.
Table 1: Socio-economic and dietary characteristics of mother-infant pair households
Characteristics
|
NEP-area
(n=73)
|
non-NEP-area
(n=67)
|
P value
|
|
M ± SD or %
|
M ± SD or %
|
|
Head of household gender
|
|
|
|
Male
|
100 (73)
|
95.5 (64)
|
0.068
|
Female
|
-
|
4.5 (3)
|
|
Number of children under 5 years
|
3.0 ± 1.4
|
3.6 ± 2.3
|
0.094
|
Socio-economics status
|
|
|
|
Low
|
37.0 (27)
|
29.8 (20)
|
0.096
|
Medium
|
38.4 (28)
|
28.4 (19)
|
|
Acceptable
|
24.7 (18)
|
41.8 (28)
|
|
Household food insecurity
|
|
|
|
Food insecure
|
38.4 (28)
|
37.3 (25)
|
0.733
|
Mildly food insecure
|
12.3 (9)
|
14.9 (10)
|
|
Moderately food insecure
|
16.4 (12)
|
10.4 (7)
|
|
Severely food insecure
|
9.6 (7)
|
11.9 (8)
|
|
M ± SD mean ± standard deviation, % percentage
The characteristics of mothers and infants by group are detailed in Table 2. The mean age of the mothers (25 ± 5 years) was comparable between the two areas. Mothers were mostly multiparous (73%) and the distribution of ethnic groups was identical in both areas, with a predominance of Wolof/Lebou ethnic (68.5% NEP-area vs. 65.7% non-NEP-area). More than half (63.6%) of the mothers were illiterate and very few (3.6%) had attained middle or higher education. The proportion of mothers living in polygamous households was significantly higher in the NEP intervention area (45.2%) than in the non-NEP-area (25.4%) (p=0.014). Participation in behavior change communication activities was significantly higher among mothers in the NEP-area (68.5%) compared to those in the non-NEP-area (31.3%) (p<0.001).
For infants, the mean age was 4.9 ± 0.5 months, 52.9% were boys and almost all were correctly vaccinated (99.3%) with no difference between the two areas. Regarding morbidity during the last 15 days prior to the study, the prevalence of diarrhoea and acute respiratory infection were significantly higher among infants in the non-NEP-area compared to those in the NEP-area (p<0.05), respectively.
Table 2: Mother-infant pair characteristics
|
NEP-area
(n=73)
|
non-NEP-area
(n=67)
|
|
Mothers
|
M ± SD or %
|
M ± SD or %
|
P value
|
Age (year)
|
26 ± 5
|
24± 5
|
0.274
|
Parity
|
|
|
|
Primiparous
|
19.18 (14)
|
34.33 (23)
|
0.042
|
Multiparous
|
80.8 (59)
|
65.7 (44)
|
|
Marital status
|
|
|
|
Married
|
98.3 (72)
|
100 (67)
|
0.336
|
Divorced/widowed
|
0.7 (1)
|
0 (0)
|
|
Ethnicity
|
|
|
|
Wolof/Lebou
|
68.5 (50)
|
65.7 (44)
|
0.153
|
Serere
|
11.0 (8)
|
10.4 (7)
|
|
Pulaar
|
12.3 (9)
|
22.4 (15)
|
|
Others
|
8.2 (6)
|
1.5 (1)
|
|
Education
|
|
|
|
None
|
65.7 (48)
|
61.2 (41)
|
0.485
|
Primary school
|
26.0 (19)
|
23.9 (16)
|
|
Secondary school
|
6.8 (5)
|
9.0 (6)
|
|
High school/University
|
1.4 (1)
|
6.0 (4)
|
|
Mother with one or more co-wives
|
45.2 (33)
|
25.4 (17)
|
0.014
|
Participation in the BCC sessions
|
68.5
|
31.3
|
0.000
|
Infants
|
|
|
|
Age (month)
|
4.9 ±0.5
|
4.9 ± 0.5
|
|
Sex
|
|
|
|
Boys
|
49.3 (36)
|
56.7 (38)
|
0.381
|
Girls
|
50.7 (37)
|
43.3 (29)
|
|
Immunizationa
|
100 (73)
|
98.5 (66)
|
|
Morbidity
|
|
|
|
Diarrhoea
|
30.1 (22)
|
58.2 (39)
|
0.001
|
Fever
|
15.1 (11)
|
17.9 (12)
|
0.650
|
Acute respiratory infection
|
2.7
|
11.9
|
0.035
|
M ± SD mean ± standard deviation, % percentage, BCC Behavior Change Communication
aBoth BCG, polio, pentavalent, hepatitis B, and pneumococcal vaccines.
Nutritional status of mother-infant pairs
Mother’s BMI mean was similar in the two groups (22.1 ± 4.3 kg/m2) (Table 3). According to the WHO classification, 21.4% of them were underweight (BMI<18.5 kg/m2) while 16.4% and 6.4% were overweight (25<BMI<30 kg/m2) and obese (BMI>30 kg/m2), respectively. Among infants, the WHZ and LAZ were comparable between the two groups, as well as were the proportions of stunting and wasting.
Table 3: Nutritional status of the mother-infant pairs
|
NEP-area
(n=73)
|
non-NEP-area
(n=67)
|
|
Mothers
|
M ± SD or %
|
M ± SD or %
|
P value
|
BMI (kg/m2)
|
22.1 ± 4.1
|
22.1 ± 4.6
|
0.951
|
Underweight
|
19.2 (14)
|
23.9 (16)
|
0.726
|
Normal weight
|
60.3 (44)
|
50.7 (34)
|
|
Overweight
|
15.1 (11)
|
17.9 (12)
|
|
Obese
|
5.5 (4)
|
7.5 (5)
|
|
Infants
|
|
|
|
WLZ
|
-0.2 ± 1.1
|
0.08 ± 1.0
|
0.154
|
Wasting
|
8.2 (6)
|
6.0 (4)
|
0.606
|
LAZ
|
-0.5 ± 1.1
|
-0.5 ± 1.0
|
0.879
|
Stunting
|
11.0 (8)
|
7.4 (5)
|
0.476
|
M ± SD: mean ± standard deviation; %: percentage; BMI: body mass index; WLZ: weight-for-length z-score; LAZ: length-for-age z-score; Underweight: BMI < 18.5 kg/m2; normal weight: 18.5 ≥ BMI < 25 kg/m2; overweight: 25 ≤ BMI ≥29.9; obese: BMI ≥30 kg/m2; wasting: WLZ < −2 z-score; stunting: LAZ < −2 z-score
Breast milk intake, non-milk oral intake and breastfeeding practices in both area
Breast milk and water intake from sources other than breast milk as well as breastfeeding practices measured with DTM and by 24-hour recall questionnaire and infant feeding are presented in Table 4. The average breast milk intake per day was significantly higher among the infants in the NEP-area (994.7 ± 197.3 g/d) compared to those of non-NEP-area (913.6 ± 222.8 g/d) (p=0.023). But the daily intake of water from sources other than breast milk consumed by the infants was comparable between the two areas.
According to the deuterium dilution method, 37% and 28.4% of infants were exclusively breastfed in the NEP-area and non-NEP-area, respectively. However, according to the mothers' declaration, 46.6% of the infants in the NEP-area and 44.8% of those in the non-NEP-area were exclusively breastfed. No difference was observed in exclusive breastfeeding practices between the areas, regardless of the evaluation method. Other practices such as early initiation of breastfeeding, giving water to the infant and early introduction of complementary feeding were comparable between the two groups.
Table 4: Breast milk intake and breastfeeding practices
|
NEP-area
(n=73)
|
non-NEP-area
(n=67)
|
P value
|
Human milk intake (HMI) (g/d) M±SD
|
994.7 ± 197.3
|
913.6 ± 222.8
|
0.023
|
Non-milk oral intake (NOMI) (g/d) Me [25e – 75e]
|
123 [44 – 226]
|
155 [75 – 260]
|
0.105
|
Breastfeeding practices (DTM) (%)
|
EBF
|
37.0 (27)
|
28.4 (19)
|
0.278
|
Non-EBF
|
63.0 (44)
|
71.6 (46)
|
|
Breastfeeding practices (24h-Recall) (%)
|
Yes
|
46.6 (39)
|
44.8 (37)
|
0.8631
|
No
|
53.4 (36)
|
55.2 (34)
|
|
Infant feeding practices
|
|
|
|
early initiation of breastfeeding
|
74.0 (54)
|
70.1 (47)
|
0.614
|
Infant receiving water
|
37.0 (27)
|
49.2 (33)
|
0.143
|
eating porridge
|
15.1 (11)
|
20.9 (14)
|
0.369
|
eat the family meal
|
1.4 (1)
|
4.5 (3)
|
0.270
|
M ± SD: mean ± standard deviation; Me [25e – 75e]: median with interquartile range; %: percentage; DTM: deuterium-oxide turnover method; g/d: gram/day
Comparison of breastfeeding practices measured by DTM and maternal 24h-Recall
For the comparison between the two methods of measuring breastfeeding practices, predominantly and partially breastfed infants were grouped into a single group as non-exclusively breastfed infants (Non-EBF) (Table 5). The results show a significant difference between the exclusive breastfeeding rate measured by the deuterium dilution method and that obtained by the mothers' recall (p=0.016; 95%CI [-0.28; -0.01]).
Table 5: Comparison of breastfeeding practices between the two methods
Breastfeeding practices by methods
|
DTM
|
24h-Recall
|
P value
|
EBF %(n)
|
32.9 (46)
|
45.7 (64)
|
0.016
|
Non-EBF %(n)
|
67.1 (94)
|
54.3 (76)
|
|
EBF: exclusively breastfeeding infants; Non-EBF: Non-exclusively breastfeed; DTM: deuterium-oxide turnover method; %: percentage
Factors associated with infant breast milk intake
All socio-economic and dietary variables as well as those related to maternal and infant characteristics that were significant at P<0.05 in the binary mixed model linear regressions with infant’s milk intake were entered into multiple linear regression analyses. The result in Table 6 shows that participation in behavior change communication activities is associated with a higher consumption of breast milk by infants of 80.0 g/d compared to those whose mothers did not participated (p=0.013). The type of breastfeeding was also associated with infant milk intake. Non-exclusively breastfed infants consumed 74.4 g/d less milk compared to exclusively breastfed infants (p=0.035). Giving infants porridge reduced their breast milk intake by 182.6 g/d (p=0.000). Significant negative associations were found between lower milk intake and infant nutritional status. Stunted and wasted infants had a lower breast milk intake of 119.6 g/d (p=0.023) and 199.4 g/d (p=0.001) respectively, compared to infants with normal nutritional status.
Table 6: Factors associated with infant’s breast milk intake
HMI (g/d)
|
β coefficient
|
95% CI
|
P value
|
BCC
|
80.0
|
16.8 ; 143.3
|
0.013
|
EBF
|
74.4
|
5.4 ; 143.4
|
0.035
|
Porridge consumption
|
-182.6
|
-263.0 ; -102.1
|
0.000
|
Stunting
|
-119.6
|
-222.8 ; -16.3
|
0.023
|
Wasting
|
-199.4
|
-315.8 ; -82.9
|
0.001
|
HMI: Human milk intake, g/d: gram/day, BCC: behavior change communication, EBF: exclusive breastfeeding