Insulin Fermentation: Pollution's Unseen Culprit?

The impact of insulin production and diabetes management on the environment is a growing area of concern. With an estimated 537 million adults living with diabetes worldwide, the waste generated from needles, syringes, lancets, and packaging is significant. Additionally, the environmental impact of insulin production itself, including the fermentation process, has come under scrutiny. While there is limited direct evidence of the pollution caused by insulin fermentation, the broader impact of diabetes on the environment is undeniable, from the overuse of land and water resources to the contribution to air and water pollution. Furthermore, recent studies suggest a link between environmental pollutants and insulin resistance, indicating a potential two-way relationship between insulin production and environmental degradation.

Insulin pump therapy waste incineration

Insulin pump therapy, or continuous subcutaneous insulin infusion (CSII), is a treatment that requires the regular changing of infusion sets to avoid skin irritations and other adverse events. This process has been identified as a potential burden to the environment, particularly due to the incineration of discarded products.

The environmental impact of insulin pump therapy has been assessed through a lifecycle concept, which weighs the consumption and rarity of materials used in the therapy. This includes the analysis of the waste volume, recyclability, and associated loss of resources. The investigation revealed that the environmental loss of resources from insulin pump infusion sets is comparable to the waste generated from consuming one disposable cup of coffee per day and significantly lower than drinking one soft drink in an aluminium can per day.

The analysis considered various infusion sets and patch pumps, such as Inset30, InsetII, Comfort, Quick-set, Cleo, and Omnipod. The theoretical resource consumption for each device was calculated based on the assumption that they were changed every three days. The individual components were identified and weighed using a high-precision balance.

The disposal routes of waste fractions produced by tube-free insulin pump systems were also examined. The waste fractions included wastepaper, lightweight plastic packaging, waste electrical and electronic equipment (WEEE), and residual waste. While the first three fractions were assumed to undergo recycling, the residual waste was sent for incineration in a waste incineration plant (WIP). The small particle size of metals in the residual waste made recovery from incineration residue unlikely, resulting in a 0% metal recycling rate for this fraction.

Overall, the incineration of discarded products from insulin pump therapy contributes to the environmental impact of this treatment. The loss of natural resources through incineration and the potential for pollution from the release of pharmaceutical chemicals into the environment are areas of concern.

Air pollution and insulin resistance

The metabolic disruptor hypothesis suggests that environmental pollutants may be risk factors for metabolic diseases. Insulin resistance is involved in most metabolic diseases, and current healthcare prevention programs predominantly target insulin resistance or its risk factors. Therefore, a critical analysis of the role of pollutants in insulin resistance is important for the future management of metabolic diseases.

Several studies have investigated the potential association between pollutants and markers of insulin sensitivity. The most convincing evidence for a positive association of exposure to environmental pollutants and insulin resistance is with phthalates and air pollutants.

Recent studies specifically designed to investigate the effect of pollutants on insulin sensitivity show a potential causation of insulin resistance. However, all studies emphasized the need for experimental evidence providing proof of causation of insulin resistance, diabetes, or obesity by pollutants.

A systematic review and meta-analysis of six cohort studies published before January 2018 assessed the association between air pollutants, including PM2.5, NO2, and PM10, and insulin resistance. The results showed a significant positive association between exposure to these air pollutants and insulin resistance, with a 1 μg/m3 increase in NO2 associated with a 1.25% change in the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR).

Additionally, long-term exposure to traffic-related air pollution has been linked to increased insulin resistance in children. Children are particularly vulnerable to the effects of air pollution due to their larger lung-to-body volume ratio, more permeable airway epithelium, and less developed lung defense mechanisms. Studies have shown that adults and youth exposed to higher levels of nitric oxide, NO2, and PM2.5 had higher rates of insulin resistance and type 2 diabetes mellitus (T2DM).

In summary, while the exact mechanisms remain to be fully elucidated, current evidence suggests a positive association between exposure to air pollution and insulin resistance, with potential implications for the development of metabolic diseases. Further research is needed to establish causation and inform the development of effective preventive measures.

Environmental pollutants and insulin resistance

The metabolic disruptor hypothesis suggests that environmental pollutants may be risk factors for metabolic diseases. As insulin resistance is involved in most metabolic diseases, the role of pollutants in insulin resistance is important to understand for the future management of metabolic diseases.

Several studies have investigated the potential association between pollutants and markers of insulin sensitivity. The most convincing evidence for a positive association of exposure to environmental pollutants and insulin resistance is with phthalates and air pollutants.

A systematic review and meta-analysis of studies published before January 2018 found a positive association between exposure to air pollutants and insulin resistance. The analysis included six cohort studies that assessed air pollutants, including PM2.5, NO2, and PM10. The results showed that a 1 μg/m3 increase in NO2 was associated with a significant 1.25% change in insulin resistance. Similarly, a 1 μg/m3 increase in PM10 was associated with a significant 2.77% change in insulin resistance.

Another systematic review and meta-analysis, published in 2023, specifically investigated the potential effects of long-term exposure to air pollution on insulin resistance. The study found that long-term exposure to air pollution is associated with increased odds of insulin resistance, with inhalable particulate matter having a greater impact on insulin resistance than other air pollutants.

The development of dedicated in vitro and ex vivo screens to allow animal-sparing and time- and cost-effective bottom-up screening is a major future research need.

Insulin resistance and metabolic diseases

Insulin resistance (IR) is a condition where cells do not respond normally to insulin, leading to elevated blood sugar levels as glucose cannot enter the cells easily. IR is characterized by insulin-mediated blood glucose management disorders, blood glucose utilization disorders, abnormal lipid accumulation, and increased lipid decomposition activities in adipocytes. IR is closely associated with metabolic diseases and plays a crucial role in their development and progression.

Metabolic syndrome is a cluster of conditions, including increased blood pressure, high blood sugar, excess abdominal fat, and abnormal cholesterol or triglyceride levels, that elevate the risk of cardiovascular disease, Type 2 diabetes, and stroke. IR is a significant contributor to metabolic syndrome, and certain factors can increase the chances of developing this syndrome, including age, ethnicity, obesity, diabetes, and other diseases such as non-alcoholic fatty liver disease, polycystic ovary syndrome, and sleep apnea.

IR is associated with various metabolic diseases, including diabetes, hypertension, non-alcoholic fatty liver disease, tumors, and cardiovascular disease. Prolonged overexposure to insulin itself can trigger IR, and both IR and Type 2 diabetes are linked to obesity, particularly high levels of intra-abdominal fat. Additionally, physical inactivity can contribute to IR as muscles utilize glucose and stored glucose (glycogen) for functioning. Exercise enhances the body's sensitivity to insulin and builds muscle that can absorb more blood glucose.

Genetics also play a role in IR and metabolic diseases. Inherited genes can contribute to IR, obesity, high blood pressure, and high cholesterol. Environmental factors, such as exposure to pollutants, may also be risk factors for metabolic diseases and IR. Recent studies suggest a potential causative link between pollutant exposure and IR, especially with phthalates and air pollutants.

Treating metabolic syndrome and IR involves lowering the risk of cardiovascular disease and Type 2 diabetes through medications and lifestyle changes. Lifestyle modifications include maintaining a healthy weight, engaging in regular physical activity, and adopting a nutritious diet with fruits, vegetables, lean protein, and whole grains. These changes can help manage conditions contributing to metabolic syndrome and improve insulin sensitivity.

Diabetes and environmental impact

Environmental factors play a role in the development of diabetes. These factors include air pollution, polluted water, soil, an unhealthy diet, stress, lack of physical activity, vitamin D deficiency, exposure to enteroviruses, and damage to immune cells.

Recent studies have specifically investigated the effect of pollutants on insulin sensitivity and show a potential causation of insulin resistance. The most convincing evidence for a positive association of exposure to environmental pollutants and insulin resistance is with phthalates and air pollutants. Higher insulin levels in early childhood are associated with an increased risk of type 2 diabetes during adult life exposure to air pollutants.

The disposal of insulin pump infusion sets also contributes to the environmental impact of diabetes. The regular change of infusion sets every 2-3 days to avoid skin irritation and other technical problems creates waste. The incineration of these discarded products results in the loss of natural resources.

Additionally, geographic characteristics such as the availability of hills and slopes in a neighbourhood can influence physical activity levels, which in turn can impact the risk of developing type 2 diabetes. Neighbourhood walkability, green space, and area-level socioeconomic deprivation have also been associated with the risk of type 2 diabetes.

Further research is needed to fully understand the relationship between environmental factors and type 2 diabetes, which can inform interventions and contribute to urban planning for a healthier living environment.

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