Introduction

Proper nutrition of children can be considered as a guarantee of the future health of the nation^1,2,3. Breast milk is an ideal food for newborns and infants^4,5. It serves as a source of all easily digestible nutrients and biologically active compounds necessary for a child^6,7. To provide support to mothers in the area of breastfeeding, which should be carried out by maternal and child health services, World Health Organization (WHO) and United Nations International Children's Emergency Fund (UNICEF) specialists developed “Ten principles of successful breastfeeding”, which are used in more than 150 countries^8-10.

Even though the duration of breastfeeding is crucial for the child’s harmonious physical neuropsychiatric development, according to WHO, many mothers stop breastfeeding a few weeks after childbirth^11-13,28. The reasons for women’s continuation to breastfeed children are different and can be associated with both the child and the mother. In addition, all the reasons for continuation of breastfeeding should be divided into objective and subjective. The objective reasons for continuation may be the lack of milk, mother’s disease (lactation mastitis, taking some drugs and severe chronic diseases of the heart, lungs, kidneys or liver in the acute stage, some infections, etc.), child’s disease (hereditary metabolic disorders, deep prematurity, birth injuries, severe forms of lactase deficiency, etc.). Subjective reasons on the part of the mother include personal or socially determined reasons, such as the need to go to work or study, the fear of a woman to spoil the figure and shape of the breast, the mother’s reluctance to continue breastfeeding, etc. On the child’s part, subjective reasons for continuation can be associated with the use of a dummy and/or pacifiers, violation of feeding techniques, bottle feeding, etc.

For normal psychomotor and physical development of the child in the second half of his life, additional energy and nutrients are required, which the child can receive only when introducing additional food into the diet^14,15. After the age of six months, once the quantity and the composition of maternal milk are no longer sufficient to meet the nutritional needs of the infant, it is important and necessary to begin complementary feeding. The timing of the introduction of complementary foods has a significant impact on the child’s body¹⁶. They are set individually for each child, taking into account the peculiarities of the development of the digestive system, the excretory organs, the level of metabolism, as well as the degree of development and functioning of the central nervous system, that is, his readiness to perceive new food¹⁷. According to experts in the field of baby food, the introduction of the first products can be started as early as 4 months and as the first complementary food, as a rule, should be fruit or vegetable puree. Then, a second complementary food is introduced, which is cereal porridge. As a third complementary food, according to modern ideas about the nutrition of infants, it is advisable to use meat puree^18,19.

A model for the improvement of hypertension that remembers the impact of the intrauterine condition for fetal development as a robotic pathway contributes another measurement in causality and is of incredible intrigue. Test considers that apply moves to force fetal under nutrition in creature models have created information that help this idea²⁰.

The role of "- omics sciences" (nutrigenetics, nutrigenomics, proteomics and metabolomics) in the wellbeing status and as conceivable helpful device in ceaseless degenerative infections was investigated²¹.

The quantity of individuals with diabetes worldwide has dramatically increased during the previous 20 years. One of the most stressing highlights of this fast increment is the development of type 2 diabetes in youngsters, teenagers, and youthful grown-ups. An incorporated methodology is expected to forestall type 2 diabetes, considering its numerous sources and heterogeneity²².

Since in recent years, the age of childbirth in our country is moving to an older age group, the study of the influence of the age of the mother on the duration of breastfeeding, the reasons for refusing it and the timing of the introduction of complementary foods in the first year of life is an important topic for research. Thus, this study aimed to assess the influence of the mother’s age on the frequency of breastfeeding and the introduction of complementary foods of children in their first year of life.

Materials and Methods

The study was conducted based on 7 children’s polyclinics in St. Petersburg in 2018-2019. All children’s polyclinics (departments) were clinical bases of St. Petersburg State Pediatric Medical University of the Ministry of Healthcare of the Russian Federation.

According to the specially developed form “Questionnaire of the mother of a one-year-old child”, 1742 mothers who had one-year-old children were surveyed by random sampling. Evaluation of the distribution of respondents by age revealed that the majority of women were 25-29 years old; the proportion of them was 36.3%. There were 1.7% respondents under 20, 20-24 - 24.4%, 30-34 - 25.7%, 35-39 - 10.7%, 40 and older - 1.2%. The average age of the mother was 28.6±0.11.

In the questionnaire, in addition to the age of the mother, the actual and planned terms of breastfeeding, the duration of feeding the child with breast milk and the introduction of complementary foods in the first year of life were studied. The mother independently filled out the questionnaire after local pediatricians’ or specialist doctors’ appointments during the medical examination provided for the child who is 1 year old by Order of the Ministry of Healthcare²³.

Mathematical data processing was carried out using spreadsheets “MS Office Excel 2010”.

Results

A comparative assessment of planned and actual terms of breastfeeding duration, depending on the age of the mother is shown in figure 1.

Figure 1
lanned and actual terms of breastfeeding duration depending on the age of the mother (in months).

The study of the influence of the mother’s age on the proportion of breastfeeding withdrawal for an objective reason showed that the older the mother is, the higher is the total proportion of breastfeeding withdrawal for an objective reason. It was found that the lack of milk was the most often objective reason for which women suspend breastfeed. The proportion of breastfeeding withdrawal for an objective reason in different age groups of mothers is shown in figure 2.

Figure 2.
The proportion of breastfeeding withdrawal for an objective reason in different age groups of mothers (expressed in %)

The influence of age on subjective reasons for breastfeeding withdrawal is presented in figure 3.

Figure 3
The proportion of breastfeeding withdrawal for subjective reasons in different age groups of mothers (expressed in %)

Based on the correlation study that was done, the amount of obtained correlation coefficient was very close to 1 and also the results of T test (t>2), we can compensate that there was a direct strong correlation between the age of the mother and the proportion of continuations due to the need to go studying or working. In contrast, results showed a strong inverse correlation (t<2) between the age of the mother and the proportion of breastfeeding withdrawal due to her unwillingness to continue feeding the child with breast milk.

After the age of six months, it is important to begin complementary feeding, once the quantity and the composition of maternal milk are no longer sufficient to meet the nutritional needs of the infant. The inadequate introduction of foods in the diet of the infant may lead to damaging consequences to health, especially when the offer is made before the complete physiological development. Regarding the nutritional aspect, it is unfavorable, since it increases the risk of contamination and allergic reactions, interferes in the absorption of important nutrients in maternal milk, and implies in the risk of early weaning. On the other hand, the late initiation of foods is disadvantageous, since after the sixth month of life maternal milk no longer meets the energy needs of the child, leading to the deceleration of growth and increasing the risk of nutritional deficiency.

The influence of the mother’s age on the timeliness of the introduction of complementary foods in the diet of the child in the first year of life was studied. According to the recommendations of pediatricians and nutritionists, the first complementary food is advisable to start with fruit puree no earlier than 4 months old. Then vegetable and grain products are introduced into the diet^{26, 27}. It was found that most mothers gave the child fruit and vegetable puree in time (Table 1).

Table 1
Distribution of children on the timeliness of introduction of the first complementary food in a diet depending on the mother’s age (in % to total)

Age	Fruit puree				Vegetable puree
	Earlier	In time	Later	Total:	Earlier	In time	Later	Total:
Under 20	2.1	97.8	0.1	100.0	-	96.9	3.1	100.0
20-24	-	89.2	10.8	100.0	-	86.9	13.1	100.0
25-29	-	87.5	12.5	100.0	-	89.6	10.4	100.0
30-34	1.7	79.7	18.6	100.0	-	83.1	16.9	100.0
35-39	5.7	75.1	19.2	100.0	6.1	75.7	36.9	100.0
40 and older	-	25.2	74.8	100.0	-	41.3	58.7	100.0

Grain product is the second complementary food, which is introduced about a month after the first. It was revealed that the proportion of mothers who introduced cereal porridge into the diet of children early was the highest in the age group under 20 years old. According to the correlation coefficient that was determined (r_xy=0.88), there was a direct strong correlation between the age of the mother and the proportion of children who received porridge later with age increasing, the proportion of respondents who introduced the second complementary food later increases. Distribution of children on the timeliness of the introduction of the second complementary food in a diet depending on the age of the mother is presented in Table 2.

Table 2
Distribution of children on the timeliness of introduction of the second and third complementary foods in a diet depending on the mother’s age (in % to total)

Age	Porridge				Meat puree
	Earlier	In time	Later	Total:	Earlier	In time	Later	Total:
Under 20	98.5	1.2	0.3	100.0	-	0.9	99.1	100.0
20-24	-	79.0	21.0	100.0	28.6	34.3	37.1	100.0
25-29	-	78.1	21.9	100.0	-	40.6	59.4	100.0
30-34	3.1	66.7	30.2	100.0	3.4	32.7	63.9	100.0
35-39	11.1	58.3	30.6	100.0	10.3	31.1	58.6	100.0
40 and older	-	22.4	77.6	100.0	-	2.1	97.9	100.0

The distribution of children according to the timeliness of the introduction of cottage cheese paste (cottage cheese) and egg yolk into the diet, depending on the age of the mother, is presented in Table 3.

Table 3.
Distribution of children on the timeliness of introduction of cottage cheese paste (cottage cheese) and egg yolk in a diet depending on the mother’s age (in % to total)

Age	Cottage cheese paste				Egg yolk
	Earlier	In time	Later	Total:	Earlier	In time	Later	Total:
Under 20	-	96.3	3.7	100.0	0.3	94.9	4.8	100.0
20-24	4.2	29.6	66.2	100.0	3.8	39.2	57.0	100.0
25-29	5.2	20.9	73.6	100.0	6.8	33.9	59.3	100.0
30-34	11.5	32.6	65.9	100.0	7.3	36.4	56.3	100.0
35-39	13.8	17.2	69.0	100.0	21.2	24.2	54.6	100.0
40 and older	0.7	2.2	97.1	100.0	33.3	-	66.7	100.0

Fermented milk products and fish puree are not recommended before the age of eight months²⁷. Evaluation of the effect of age on the timeliness of the introduction of fermented milk products revealed the presence of strong direct correlation between age and proportion of the children who received them in time (r_xy=0.86) and a strong inverse one between age and proportion of the children who received milk products later (r_xy=-0.92). Accordingly, with the increase in the mother’s age, the proportion of children who received fermented milk products in time increases and the proportion who received them later decreases. The study of the introduction of fish puree in the diet of an infant child showed that in most cases, mothers introduced fish puree later than term. However, the proportion of mothers who gave their children fish puree later than recommended was highest among women younger than 20 and older than 40 (98.9% and 97.5%, respectively), as can be seen from Table 4.

Table 4
Distribution of children on the timeliness of introduction of fish puree and fermented milk products in a diet depending on the mother’s age (in % to total)

Age	Fermented milk				Fish puree
	Earlier	In time	Later	Total:	Earlier	In time	Later	Total:
Under 20	-	1.3	98.7	100.0	-	1.1	98.9	100.0
20-24	1.1	3.3	95.6	100.0	5.9	5.9	88.2	100.0
25-29	11.7	11.7	76.6	100.0	9.2	16.7	74.1	100.0
30-34	18.9	13.4	67.7	100.0	13.2	7.9	78.9	100.0
35-39	24.1	14.1	61.8	100.0	17.4	21.7	60.9	100.0
40 and older	-	46.7	53.3	100.0	-	2.5	97.5	100.0

DISCUSISION:

The mothers participating in the survey planned to breastfeed their babies up to a mean value of 12.5±0.08 months in maternity care facilities. When it was studied the effect of mother’s age on the planned period of breastfeeding at an obstetric clinic, the results showed that the mothers under 20 years old planned to feed for 12.4±0.11 months, between 20-24 years old for 13.5±0.08 months, 25-29 years old for 12.9±0.08 months, 30-34 years old for 12.4±0.08 months, 35-39 years old for 12.8±0.09 months, and 40 years old for 15.0±0.10 months. However, actual feeding time expressed as mean was only 5.9±0.08 months. The evaluation of actual terms of breastfeeding duration showed that mothers under 20 years old fed up to 9.0±0.11 months, 20-24 years old up to 6.1±0.08 months, 25-29 years old up to 6.9±0.08 months, 30-34 years old up to 6.2±0.08 months, 35-39 years old up to 3.4±0.09 months, and 40 years old and older up to 4.7±0.10 months (Fig. 1).

The mothers participating in the survey planned to breastfeed their babies up to a mean value of 12.5±0.08 months in maternity care facilities. When it was studied the effect of mother’s age on the planned period of breastfeeding at an obstetric clinic, the results showed that the mothers under 20 years old planned to feed for 12.4±0.11 months, between 20-24 years old for 13.5±0.08 months, 25-29 years old for 12.9±0.08 months, 30-34 years old for 12.4±0.08 months, 35-39 years old for 12.8±0.09 months, and 40 years old for 15.0±0.10 months. However, actual feeding time expressed as mean was only 5.9±0.08 months. The evaluation of actual terms of breastfeeding duration showed that mothers under 20 years old fed up to 9.0±0.11 months, 20-24 years old up to 6.1±0.08 months, 25-29 years old up to 6.9±0.08 months, 30-34 years old up to 6.2±0.08 months, 35-39 years old up to 3.4±0.09 months, and 40 years old and older up to 4.7±0.10 months (Fig. 1).

Results demonstrate that mothers under 20 had a minimum withdrawal rate of 24.3%, while those of 40 and older had a maximum withdrawal rate of 62.4%. Meanwhile, 20-24-year-old women (7.3%) and 30-34-year-old ones (8.7%) most often stopped breastfeeding because of their illness, and 35-39-year-old and 40-year-old and older mothers (3.8% and 4.5%, respectively) because of the illness of the child.

Evaluation of the influence of the mother’s age on the proportion of objective breastfeeding withdrawal from all causes revealed the presence of a direct strong correlation between the studied indicators (t>2). This means that all three indicators are similarly matched as mothers’ age increases. The same pattern was observed in the study of breastfeeding withdrawal associated with the lack of milk, and due to the disease of the child.

Among the subjective reasons for breastfeeding withdrawal, the main reasons were the mother’s unwillingness to continue breastfeeding, the child’s continuation to breastfeed and the need to go studying or working24,25. The proportion of breastfeeding withdrawal due to the reluctance of the mother to continue breastfeeding was highest in mothers under 20 (20.1%) and decreased with age. On the contrary, the proportion of breastfeeding withdrawal due to the need to go studying or working, was the lowest in mothers under 20 (5.9%) and increased with age. The highest proportion of the child’s continuation to breastfeed was 25-29 years old (18.0%) and 30-34-year-old (15.3%) mothers.

Determining the correlation coefficient to investigate the effect of age on the timeliness of the first complementary food introduction revealed the presence of a strong reverse correlation between age and the share of children who received timely fruit and vegetable purees (rxy=-0.86 и rxy=-0.87) and a strong direct one – between age and the share of children who received a puree later (rxy=0.83 и rxy=0.93). Accordingly, with the increase in the age of the mother, the proportion of children who received in time the first complementary food decreases, and the proportion of those who received fruit and vegetable puree later increases.

Experts in the field of baby food recommend using meat puree as a third complementary food, which should be introduced from 7 months of life, but not earlier than 5.5. At about the same time with meat puree, it is advisable to start giving the child cottage cheese paste (cottage cheese) and egg yolk28,29. As can be seen from Table 2, mothers of all ages introduced meat puree later than the optimal time. Moreover, the proportion of mothers below 20 years old and after 40 years old, introducing the third complementary foods later, was the highest.

Evaluation of the influence of age on the timing of the introduction of cottage cheese paste revealed that, except for mothers below 20 years old, women of all other ages introduced cottage cheese later than the term. Young mothers in 96.3% of cases gave children cottage cheese paste in time. And the largest proportion of respondents who introduced cottage cheese later was among 40 years old and older mothers (97.1%). When studying the introduction of egg yolk in the diet of the child, a similar pattern was established. Also, there was a direct strong correlation between age and the proportion of mothers who introduced yolk earlier than the optimal period (rxy=0.94). Thus, with age increasing, the proportion of respondents, who introduced yolk earlier, increases.

Conclusions

1. In obstetric hospitals, 20-24-year-old and 40-year-old and older mothers planned to feed a child with breast milk the longer period of time, however 18 to 35-year-old mothers continued breastfeeding the longest time.

2. With the mother’s age increasing the proportion of breastfeeding withdrawal due to the lack of milk increases in connection with the need to go studying or working, but the proportion of breastfeeding withdrawal related to the unwillingness of the mother to continue breastfeeding decreases.

3. The older the mother is, the later she introduces the first and second complementary foods in the diet of her child.

4. Mothers under 20 and over 40 were more likely than mothers of other age groups to introduce meat and fish puree later.

5. Almost all mothers under 20 gave children cottage cheese paste and egg yolk in time, unlike women of other age groups, who introduced these products later.

6. With the mother’s age increases, the proportion of children who received fermented milk products in time increases and the proportion who received them later decreases.

Thus, the age of the mother has a significant impact on the nutrition of children in their first year.

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