Increased blood levels of persistent organic pollutants (POP) in obese individuals after weight loss—A review

Lipophilic persistent organic pollutants (POP) are stored in adipose tissue. Following rapid weight loss such as when induced by bariatric surgery, an increased release of potential harmful lipophilic compounds into the blood circulation may occur. Weight reduction is recommended for overweight and obese individuals in order to decrease risk of weight-related health problems. However, in cases of significant weight reduction POP become mobilized chemicals and consequently may adversely affect health, including endocrine disruption. The objective of the present investigation was to estimate quantitatively the level of mobilization of POP following weight loss over time. According to literature search criteria, 17 studies were identified with 2061 participants. Data from 5 of the studies with 270 participants were used to assess the change in blood levels of POP in percent per kilogram weight loss. Weight loss in the included studies varied from 4.4 to 64.8 kg. In all studies, the majority of POP concentrations in blood were found to rise following weight reduction. Blood concentrations following weight reduction were elevated by 2–4% per kilogram weight loss for most POP examined. The increased POP levels were still elevated 12 mo after intervention. Most research in this field, including animal studies, is carried out on a single compound or group of selected compounds, not taking the “cocktail effect” into consideration. This does not reflect the true range of POP to which humans are actually exposed. Few chronic investigations have been published and, in particular, few studies were available that compared the increase in POP concentrations with clinical consequences as individuals lost weight. These limitations call for caution in interpreting results. The benefits of losing weight still far outweigh the potential adverse health risks. However, further studies are recommended to determine the clinical significance of increased blood levels of POPs following rapid and excessive weight loss, particularly for women attending weight reduction treatment before pregnancy.

亲脂性持久性有机污染物 (Lipophilic persistent organic pollutants, 简称POP) 可储存于脂肪组织中。当发生快速减重（如由减重手术 (bariatric surgery) 诱发）时，这类具有潜在危害的亲脂性化合物可能会大量释放进入血液循环。超重与肥胖人群被建议通过减重来降低与体重相关的健康问题风险。然而，当出现大幅减重时，POP会成为被动员的化学物质，进而可能对健康造成不利影响，包括引发内分泌干扰效应。本研究的目标是定量评估减重后随时间推移的POP动员水平。根据文献检索标准，共纳入17项相关研究，涉及2061名受试者。其中5项研究（涉及270名受试者）的数据被用于评估每减重1千克时血液中POP水平的百分比变化。纳入研究中的受试者减重幅度介于4.4至64.8千克之间。所有研究均显示，减重后多数POP的血液浓度出现上升。对于本次检测的多数POP而言，每减重1千克，其血液浓度会升高2%~4%。干预后12个月，POP水平的升高仍持续存在。该领域的多数研究（包括动物实验）仅针对单一化合物或特定组别的化合物展开，未考虑“鸡尾酒效应”。此类研究无法反映人类实际暴露于POP的真实范围。已发表的慢性研究寥寥无几，尤其是针对减重过程中POP浓度升高与临床结局之间关联的研究更为稀缺。上述局限性要求我们在解读研究结果时保持谨慎。减重带来的益处仍远大于其潜在的健康风险。然而，仍需开展进一步研究以明确快速与过度减重后血液中POPs水平升高的临床意义，尤其是针对妊娠前接受减重治疗的女性群体。