ASSESSMENT OF THE RELATIONSHIP BETWEEN VITAMIN D AND OVERWEIGHT IN WOMEN OF REPRODUCTIVE AGE 25-35 YEARS

ABSTRACT

The aim of the study was to determine the relationship between vitamin D (25(OH)D) deficiency and abdominal obesity in women of reproductive age, based on a study of their anthropometric data (BMI, waist circumference), as well as an in vitro blood serum analysis. At the same time, based on the results of a literature review, it was determined that in vitro studies using blood serum showed that 25(OH)D blocks adipocyte differentiation, inhibits the synthesis of a protein that ensures the transfer of fatty acids necessary for lipolysis, suppresses the activity of PPAR-y receptors, and also inhibits the expression of the free fatty acid synthetase gene, which is an important enzyme in lipogenesis. It was found that out of 114 women of reproductive age, 36 women (31.57%) were overweight, while 25 of them had vitamin D deficiency (19 women had a minor deficiency, and 6 women had a significant deficiency of vitamin D less than 12 ng/ml). In women of reproductive age preparing for pregnancy, abdominal obesity of the second and third degree was recorded in 8 people (7.02%), while all of them had a significant deficiency of vitamin D (less than 12 ng/ml).

АННОТАЦИЯ

В ходе исследования была поставлена цель определить взаимосвязь недостатка витамина D (25(OH)D) c абдоминальным ожирением у женщин репродуктивного возраста, на основании исследования их антропометрических данных (ИМТ, объем талии), а также анализа сыворотки крови in vitro. При этом, по результатам литературного обзора было определено, что исследования, проведенные in vitro с использованием сыворотки крови показали, что 25(OH)D блокирует дифференцировку адипоцитов, подавляет синтез белка, обеспечивающего перенос жирных кислот, необходимого в процессах липолиза, супрессирует активность рецепторов PPAR-y, а также подавляет экспрессию гена синтетазы свободных жирных кислот, являющейся важным ферментом липогенеза. Было выявлено, что из 114 женщин репродуктивного возраста 36 женщин (31,57%) имеют избыточную массу тела, при этом, у 25 из них наблюдается недостаток витамина D (у 19 женщин незначительный недостаток, и у 6 женщин- существенный недостаток витамина D менее 12 нг/мл). У женщин репродуктивного возраста, готовящихся к беременности, абдоминальное ожирение второй и третьей степени зафиксировано у 8 человек (7,02%), при этом у всех наблюдается существенный недостаток витамина Д (менее 12 нг/мл).

Keywords: abdominal obesity, reproductive capacity, vitamin D deficiency (25(OH)D).

Ключевые слова: абдоминальное ожирение, репродуктивная возможность, дефицит витамина Д (25(OH)D)

Research background

In modern conditions of decreasing active lifestyle, symptoms of excess weight are observed more and more often. In particular, excess weight has begun to be observed in young women of active reproductive age 25-35 years. According to a study conducted in the period 2011-2015, every fourth woman of active reproductive age in the United States suffers from excess weight. At the same time, during pregnancy, in the third trimester, women are most often subject to excess weight gain, which can negatively affect the process of childbirth, and can cause the following negative consequences [1]:

- excess weight can contribute to the appearance of a large child, which can complicate the process of childbirth;

- excess weight increases the risk of hypoxia in the fetus;

- in addition, excess weight in the mother can cause an increased risk of heart defects in the baby and contribute to the development of neurological problems.

Literature review

Research on the relationship between vitamin D deficiency and abdominal obesity has been the subject of active analysis and consideration by many scientists. Professor Bolesławska I. claims that vitamin D deficiency may be associated with abdominal obesity through its connection with processes affecting metabolic activity in the human body. Thus, she refers to the ability of vitamin D to modulate the functions of adipocytes (fat cells) and affect the distribution of fat in the body [2].

Professor Durrant L.R. believes that vitamin D deficiency may contribute to an increase in fat deposits in the abdominal area. He suggests that low vitamin D levels may lead to dysregulation of hormones such as insulin, which in turn may contribute to the accumulation and deposition of fat cells in the abdominal area [3]. Dr. Trump D.L. points to a possible connection between low vitamin D levels and an increase in visceral fat. He notes that vitamin D can play a role in regulating appetite and energy metabolism, which can affect the weight and distribution of fat cells in the abdominal area, causing abdominal obesity [4].

Mandlik R. believes that vitamin D deficiency may be associated with abdominal obesity through inflammatory processes. Inflammation caused by vitamin D deficiency can contribute to an increase in visceral fat and the development of metabolic syndrome [5]. Ballegooijen A.J. emphasizes the importance of sufficient vitamin D levels to maintain normal weight and prevent abdominal obesity. He believes that vitamin D deficiency may be associated with impaired glucose metabolism and insulin resistance, which contributes to the accumulation of fat in the abdominal area [6]. Thus, the relevance of studying the relationship between excess weight and vitamin D deficiency in women of active reproductive age is undoubted in modern conditions.

Research purpose & methods

The aim of the study is to analyze the relationship between vitamin D deficiency and excess weight in women of reproductive age 25-35 years.

For this purpose, we analyzed the data of 114 women aged 25-35 years who underwent the study before planning a pregnancy. In addition to the main tests, the respondents had the following measured:

- body mass index (kg/m2);

- weight (kg);

- waist circumference (cm).

The analysis of the vitamin D status in the blood of women was measured in the blood serum relative to the level of 25(OH)D. For the analysis, we used the electro chemiluminescent immunoassay (ECLIA) method using the ECL8000 Lifotronic analyzer.

Reference values

The results of the analysis were assessed using a number of reference values.

Body mass index was considered as the ratio of a woman's height to her weight.

Table 1.

Reference values for calculating body mass index

*Source: Bolesławska I, Kowalówka M, Dobrzyńska M, Karaźniewicz-Łada M, Przysławski J. Differences in the Concentration of Vitamin D Metabolites in Plasma Due to the Low-Carbohydrate-High-Fat Diet and the Eastern European Diet-A Pilot Study. Nutrients. 2021 Aug 13;13(8):2774. doi: 10.3390/nu13082774.

In accordance with the presented table, we took the body mass index above 40.0 kg/m² as an excessive degree of abdominal obesity. At the next stage, we will present the data for the analysis of reference values of vitamin D. For the analysis of vitamin D in the blood of women of reproductive age planning pregnancy, reference values of vitamin D in the blood serum were used in the calculation of nanograms per milliliter. For the determination of vitamin D, the electro chemiluminescent immunoassay (ECLIA) method was used using the ECL8000 Lifotronic analyzer.

Table 2.

 Reference values for calculating vitamin D in blood serum (25(OH)D)

*Source: Bolesławska I, Kowalówka M, Dobrzyńska M, Karaźniewicz-Łada M, Przysławski J. Differences in the Concentration of Vitamin D Metabolites in Plasma Due to the Low-Carbohydrate-High-Fat Diet and the Eastern European Diet-A Pilot Study. Nutrients. 2021 Aug 13;13(8):2774. doi: 10.3390/nu13082774.

The study involved 114 women of active reproductive age (25-35 years) who voluntarily participated. The study was conducted under the following conditions:

1) anonymity;

2) voluntary participation.

Research results

As a result of the study, it was determined that a certain proportion of the examined women who were overweight, as well as with various degrees of abdominal obesity, had varying degrees of vitamin D deficiency.

Table 3.

Study Results

* Own Studies

Discussion

According to the presented analysis, it can be concluded that with increasing age of women, the risk of abdominal obesity also increases. If women at a younger age (27.4±0.28 years) have excess body weight, while only 3 women have abdominal obesity grade 1, then in women over 31 years old, the risk of obesity increases, as does the lack of vitamin D. We also found that vitamin D deficiency contributes to abdominal obesity because vitamin D inhibits the differentiation of preadipocytes into adipocytes by reducing the expression of key adipogenic transcription factors such as PPARγ and C/EBPα. 25(OH)D increases the expression of genes associated with mitochondrial biogenesis and thermogenesis such as UCP1, which contributes to increased energy expenditure and decreased fat accumulation. Vitamin D improves insulin sensitivity by increasing the expression of insulin receptor substrates (IRS1 and IRS2), which improves glucose metabolism and reduces hyperinsulinemia, a key factor in the development of abdominal obesity.

Conclusion

In the course of the study, we set the goal of determining the relationship between vitamin D (25(OH)D) deficiency and abdominal obesity in women of reproductive age. At the same time, according to the results of the literature review, it was determined that studies conducted in vitro using blood serum showed that 25(OH)D blocks adipocyte differentiation, inhibits the synthesis of a protein that ensures the transfer of fatty acids necessary in lipolysis processes, suppresses the activity of PPAR-y receptors, and also inhibits the expression of the free fatty acid synthetase gene, which is an important enzyme in lipogenesis. In other words, women with excess body weight and abdominal obesity are more likely to have a deficiency of 1,25-dihydroxyvitamin D. The results of the presented study do not contradict previously obtained data. We found that out of 114 women of reproductive age, 36 women (31.57%) were overweight, while 25 of them had vitamin D deficiency (19 women had a minor deficiency, and 6 women had a significant deficiency of vitamin D less than 12 ng/ml). Among women of reproductive age preparing for pregnancy, abdominal obesity of the second and third degree was recorded in 8 people (7.02%), while all of them had a significant deficiency of vitamin D (less than 12 ng/ml). To prevent 25(OH)D deficiency, it is recommended to take vitamin D in an amount of at least 400 IU per day, and in some cases, recommendations can be up to 1000 IU.

References:

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