Alkaline phosphatase–immunoglobulin conjugate binds to lipids in vitro, independent of antibody selectivity

Elevated levels of nitrous dioxide are associated with lower AMH levels: a real-world analysis

STUDY QUESTION

Are there any associations between environmental pollutants and ovarian reserve, expressed by anti-Mullerian hormone (AMH) serum levels?

SUMMARY ANSWER

In this first real-world approach to demonstrate the relationship between air pollutants and serum AMH levels, adverse associations were observed for nitrogen dioxide (NO2) but not with particulate matter.

WHAT IS KNOWN ALREADY

In recent years, air pollution has emerged as a potential disrupter to the homeostasis of physiological hormones, possibly affecting human reproduction. Although the influence of age and smoking on AMH levels is largely accepted, the relationship between AMH and the environment has not currently been established.

STUDY DESIGN, SIZE, DURATION

A longitudinal, observational, retrospective, real-world study was carried out, including all AMH measurements performed in a single laboratory from January 2007 to October 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Serum AMH data were connected to patients' age and residential address, to include air pollution data after geo-localisation. The air pollution considered daily particulate matter (PM) and NO2 values.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1463 AMH measurements were collected (mean 1.94 ng/ml, median 0.90 ng/ml). AMH was inversely related to patients' age in women older than 25 years (adjusted R-squared 0.120, P < 0.001), but not in those younger than 25 years (adjusted R-squared 0.068, P = 0.055). AMH levels were inversely related to environmental pollutants, such as PM10 (Rho = -0.088, P = 0.001), PM2.5 (Rho = -0.062, P = 0.021) and NO2 (Rho = -0.111, P < 0.001). After subdividing the dataset into quartiles for PM10 and PM2.5, the influence of age on AMH serum levels was found to be a stronger influence than that exerted by PM (P = 0.833 and P = 0.370, respectively). On the contrary, considering NO2 quartiles, higher AMH levels were observed in third quartile compared to fourth quartile, even after adjustment for age (P = 0.028), indicating a stronger influence of NO2 exposure on AMH serum levels. Considering an AMH cut-off of 0.3 ng/ml, a significant higher frequency of women with severe ovarian reserve reduction in the fourth quartile was shown only for NO2 (P = 0.010).

LIMITATIONS, REASONS FOR CAUTION

Several limitations should be underlined, such as the lack of information about work and life habits of each patient and the retrospective nature of the analysis performed on real-world data.

WIDER IMPLICATIONS OF THE FINDINGS

Although the genetic component is highly predictive for defining the ovarian reserve at birth, potentially modifiable environmental factors could influence the rate of decline in AMH and ovarian reserve during adulthood.

STUDY FUNDINGCOMPETING INTEREST(S)

Authors have neither funding nor competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Chronic kidney disease is a main confounding factor for 25-vitamin D measurement

Background:

Current guidelines recommend assessment of 25-vitamin D status in patients with chronic kidney disease (CKD). Although significant differences among assays have been described, the impact of CKD on this variability has never been tested.

Methods:

We tested the variability between two 25-vitamin D assays in patients with CKD (eGFR < 60 mL/min/1.73m²) who had consecutive 25-vitamin D measurements in 2015 (Assay 1 - Diasorin LIASON 25 TOTAL - D assay^®) and 2016 (Assay 2 - Beckman Coulter Unicel Xl 800^®). The cohort consisted of 791 adult patients (122 with normal renal function and 669 with CKD - 33, 30, and 37% in stages 3, 4, and 5 on dialysis, respectively).

Results:

Levels of 25-vitamin D were lower and the prevalence of hypovitaminosis D using assay 1 was higher than using assay 2 in patients with CKD, regardless of similar levels of calcium, phosphate, and parathyroid hormone. As kidney function decreased, the percentage of disagreement between the assays increased.

Conclusion:

There is a noteworthy variability between assays in patients with CKD such that the diagnosis of hypovitaminosis D is modified. The mechanism behind this result is still unclear and might be due to a possible interference in the analytical process. However, the clinical significance is unquestionable, as the supplementation of vitamin D can be erroneously prescribed to these patients.

Multiple admissions to the coronary care unit due to falsely elevated cardiac troponin

The measurement of cardiac troponin, released from injured cardiomyocytes, is of paramount importance in the diagnosis of acute myocardial infarction. Elevated troponin can be encountered, however, in patients with cardiomyopathy, significant cardiac arrhythmias, vasculitis, right-sided heart strain, critical systemic illnesses, stroke, drug toxicity (such as Adriamycin), poisons (such as snake venoms), renal failure, seizure, and rhabdomyolysis. If the clinical picture is not consistent with any of these causes, a false-positive result should be considered. We herein describe a 94-year-old man with a prior history of coronary artery disease who presented with altered mental status and was found to have a persistently high troponin level resulting in three admissions to the coronary care unit for various noncardiac complaints. Because of discordance between clinical and laboratory data, immunological interference due to heterophile antibodies in the locally used assay (AccuTnI+3, Beckman Coulter) was suspected. The same serum sample tested on a different assay (Elecsys Troponin I Assay, Roche) resulted in an undetectable cardiac troponin I level, thus confirming the diagnosis.