1. Fatima Jinnah Medical University, Lahore, Pakistan; amanattahira@gmail.com
2. School of Allied Health Sciences, Children Hospital Lahore, Pakistan; ahmadtayyaba2@gmail.com
3. Fatima Jinnah Medical University, Lahore, Pakistan; zahida_opetsurge@gmail.com

*             Correspondence: ahmadtayyaba2@gmail.com

Keywords: low birth weight, diabetes mellitus, adult onset T2DM, SLR

1. INTRODUCTION

Diabetes is a long-term metabolic illness marked by high blood glucose (blood sugar) levels. Serious damage to the heart, blood vessels, eyes, kidneys, and nerves can result from diabetes over time. The most prevalent kind of diabetes, known as type 2 diabetes, primarily affects adults and is brought on by insufficient or resistant insulin production [1]. Recent findings have sparked a great deal of interest in the possibility that birth weight can serve as a type 2 diabetes predictions. The Pima Indians, who have a high frequency of gestational diabetes, have a U-shaped curve, with both high and low birth weights associated with the condition, despite the fact that some populations demonstrate a negative correlation between birth size and the illness. The relationship between height and gestational diabetes has also been the subject of conflicting research; nonetheless, Latina women in California have shown a strong correlation between tall and glucose levels [2]. Without a doubt, adult conditions like type 2 diabetes and hypertension that are marked by insulin resistance are linked to low birth weight [3]. Research in the past ten years has mostly focused on examining the function of the intrauterine environment, with the suggestion that starvation during fetal development causes a metabolic reprogramming that is irreversible [4]. The “fetal insulin hypothesis,” which we put forth, postulates that birth weight and size may be influenced by gene variants that cause variations in insulin resistance or secretion in the normal population. These gene variants may also have an effect on insulin-mediated fetal growth. It is critical to ascertain the proportional contribution of genes vs the intrauterine environment to this connection. This is not only a scholarly discussion; rather, it is an essential first step toward comprehending the causes of adult diseases and creating effective preventative measures [5].

2. MATERIALS AND METHODS

The study’s protocol was registered on PROSPERO, and reporting criteria for PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) would be adhered to. The articles will be cited in the Vancouver fashion. Search engines such as PUBMED, Google Scholar, and Science-direct were used to review the published articles from around the globe. The research was carried out in January 2023. The original publications from many parts of the globe that discussed the connection between low birth weight and adult-onset diabetes mellitus served as the basis for our investigation.

Sample Selection

The articles which are free to read were included. The articles with study design (cohort, systematic review, descriptive studies) were included. The articles with similar title, objectives and information targeting the adults having diabetes mellitus and their association with low birth weight and the factors involved were included. Articles whose title didn’t fulfill study were excluded. The articles with study designs (cross-sectional, interventional studies, case- reports), editorial reviews, letters of communications, and grey literature will be excluded. Articles published in language other than English was also excluded. In line with the purpose of this review, the authors separately extracted data regarding quantity, features, and evidence sources from the included papers. Included are specifics like the author, the year, the nation, the sample cohort, the sample size, the age of the participants, the study chronology, the scales or instrument, the diagnostic technique or screening tool, the stated prevalence of diabetes mellitus in individuals with low birth weight, and any other risk factors. The same authors chose which data to review and vetted any full-length articles.

3. RESULTS AND DISCUSSION

This systematic review investigates the results of a number of studies conducted in an effort to ascertain the exact nature of the relationship between low birth weight risks of type 2 diabetes mellitus in humans. From the 17 papers reviewed the existence of a positive relationship between decreases in birth weight and increased incidence of type 2 diabetes mellitus becomes evident. All papers reviewed point towards this finding. The wide geographic distribution of these studies (North America, South America, Europe, East Asia) suggests that this is not limited to a single race or ethnicity, rather is a species-wide phenomenon. This association was reported, by study 1, to be stronger in females than in males [6]. Regarding the exact nature of the relationship between birth weight and risk of type 2 diabetes mellitus the studies are relatively more conflicted. Of the studies presenting a mathematical relationship between birth weight and type 2 diabetes mellitus risk, some describe an inverse linear relationship between the two, while others describe a U-shaped relationship. Among those presenting an inverse linear relationship, 7 describes the low percentage of participants with birth weights exceeding 4000 g as a possible cause for failure of observation of the U-shaped relationship described in recent meta-analyses [7]. In contrast, study4 reports existence of both an inverse linear relationship and U-shaped relationship depending on the geographic distribution of the participants involved [8]. It also proposes the environment as a causative factor that led to the development of these disparities. Notwithstanding these differences, the largest by far, a meta-analysis, describes the relationship as J-shaped [9]. In conclusion, it can be inferred that, in most cases, it is safe to assume a J-shaped relationship between birth weight and type 2 diabetes mellitus, with lower birth weights being much more strongly correlated to risk of developing type 2 diabetes mellitus than the higher end of the spectrum. Although, study 8 reports a varying effect of birthweight on the risk of developing type 2 diabetes in different age groups, with a U-shaped relationship in some age groups and an inverse linear in others. This may be a possible cause for the development of the J-shaped curve [10]. With regards to possible mechanisms for the correlation between low birth weight and development of type 2 diabetes mellitus, 5 proposes the existence of an adverse intrauterine environment which in turn leads to both decreased birth weight and also a decrease in the number of functional Beta cells of the pancreas. This will resultantly lead to decreased insulin sensitivity [11]. In contrast, study 9 mentioned the proposal of reduced muscle mass and muscle insensitivity to insulin in those of lower birth weights as possible mechanisms for this association. This theory in particular also accounts for their finding of increased incidence of type 2 diabetes with low weight gain between birth and 2 years (particularly in the first 6 months) in contrast to an increased incidence observed for higher weight gains between the ages of 2-11 since despite most of its development being completed during gestation, skeletal muscle continues to develop for several months after birth, whilst between the ages of 2-11 greater weight gains contribute to increased fat mass rather than muscle mass [12]. On the other hand, study 7 demonstrated the mediation of this association by genetic variations. This effect of genetic factors was also reported by studies 17 and 12. Regarding its interaction with other factors, studies 3 and 13 both discussed preterm birth and reported that individuals who had low birth weights and were also preterm or small-for-gestational-age (SGA) have an increased risk of acquiring type 2 diabetes mellitus [8]. Also, studies 16, 10, 15, and 8 reported a higher incidence of development of type 2 diabetes mellitus in individuals who were born with low birth weights and were also overweight/obese than in individuals who simply had low birth weights [13]. Whilst study 8 found that greater BMI despite adding to type 2 diabetes incidence did not explain the effect of low birth weight on it, study 14 failed to discover a direct relationship between low birth weight and adult insulin resistance parameters but instead found that a higher fat mass after a higher birth weight, in contrast to a higher fat mass after a lower birth weight, had a smaller effect on these parameters, thus implying an effect of low birth weight on type 2 diabetes incidence mediated via adult body composition. Finally, study 9 reports an interaction of low birth weight with low weight gain between birth and 2 years age, with low birth weight augmenting the increased incidence of type 2 diabetes observed in individuals demonstrating low weight gain between birth and 2 years [13].

4. CONCLUSION

Birth weight is inversely proportional to development of diabetes mellitus i.e., lower the birth weight greater will be the risk of diabetes in adults.

REFERENCES

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