24 h urinary creatinine excretion during pregnancy and its application in appropriate estimation of 24 h urinary iodine excretion

Exposure of pregnant women to neonicotinoids in Wenzhou City, East China: A biomonitoring study

BACKGROUND

China produces and consumes a large amount of neonicotinoids. A non-negligible exposure to neonicotinoids might occur for Chinese pregnant women, but relevant data remain limited.

OBJECTIVE

To investigate the exposure to neonicotinoids by urinary biomonitoring in pregnant women from Wenzhou City, East China.

METHODS

We selected 432 pregnant women in Wenzhou City in 2022. A total of eight parent neonicotinoids and four metabolites were determined in single spot urine by liquid chromatography coupled to mass spectrometry. Basic characteristics, physical activity, pre-pregnant body mass index, and intake of drinking water and food were investigated by the questionnaire. Health risk was assessed by hazard quotient (HQ) and hazard index (HI) based on human safety thresholds derived from different health endpoints.

RESULTS

Neonicotinoids and their metabolites in urine had a detection frequency between 0 % and 80.1 %. At least one neonicotinoid or metabolite was detected in 93.5 % of urine samples. Except for clothianidin (51.2 %) and N-desmethyl-acetamiprid (80.1 %), the detection frequencies of other neonicotinoids and metabolites ranged from 0 % to 43.8 %. The summed concentrations of all neonicotinoids and their metabolites ranged from < LOD to 222.83 μg/g creatinine with the median concentration of 2.58 μg/g creatinine. Maternal age, educational level, occupation, household income, screen time, and pre-pregnant body mass index were associated with detection frequencies or concentrations of neonicotinoids and their metabolites. Pregnant women with higher consumption frequencies of wheat, fresh vegetable, shellfish, fresh milk, and powdered milk had higher detection frequencies of neonicotinoids and their metabolites. Both HQ and HI were less than one.

CONCLUSIONS

Overall, pregnant women in Wenzhou City showed a notable frequency of exposure to at least one neonicotinoid, although the exposure frequency for each specific neonicotinoid was generally low. Several food items derived from plants and animals were potential exposure sources. A low health risk was found based on current safety thresholds.

Iodine intake in the Swiss population 100 years after the introduction of iodised salt: a cross-sectional national study in children and pregnant women

PURPOSE

The Swiss voluntary salt iodisation programme has successfully prevented iodine deficiency for 100 years, but dietary habits are changing and today only one-third of processed foods contain iodised salt. We aimed to monitor the current iodine status in children and pregnant women.

METHODS

We conducted a nationwide cross-sectional study in children (6-12 years) and pregnant women and measured the urinary iodine concentration (UIC) in spot urine samples. We estimated the iodine intake using UIC and urinary creatinine concentration (UCC) and determined the prevalence of intakes below the average requirement (AR) using the SPADE method. We measured dried blood spot (DBS) thyroglobulin (Tg), TSH and total T4 in pregnant women.

RESULTS

The median UIC was 127 μg/L (bootstrapped 95% CI 119, 140, n = 362) in children and 97 μg/L (bootstrapped 95% CI 90, 106, n = 473) in pregnant women. The estimated prevalence of inadequate iodine intake (< 65 μg/day) was 5.4% (bootstrapped 95% CI 0.0, 14.6) in children. Half (47%) of the women consumed iodine-containing multivitamin and mineral supplements (≥ 150 μg/day). Compared to non-users, users had higher median UIC (129 vs. 81 μg/L, P < 0.001), lower prevalence of inadequacy (< 160 μg/day; 0.2 vs. 31%) and lower DBS-Tg (23 vs. 29 μg/L, P < 0.001). All women were euthyroid.

CONCLUSIONS

The Swiss diet and current salt fortification provides adequate iodine intake in children, but not in all pregnant women. Iodine supplements cover the dietary gap in pregnancy but are not universally consumed. Therefore, improved use of iodised salt in processed foods is desired to ensure adequate iodine intake in all population groups. This trial was registered at clinicaltrials.gov as NCT04524013.

Source and health risk of urinary neonicotinoids in Tibetan pregnant women

High altitude could influence the level of exposure to neonicotinoids, but relevant data remain limited for people living in Tibet. We investigated 476 Tibetan pregnant women from Lhasa of Tibet, China in 2021 and measured eight neonicotinoids and four metabolites in urine. Food consumption was investigated by a food frequency questionnaire. Health risk was assessed by using hazard quotient (HQ) and hazard index (HI) based on acceptable daily dose or chronic reference dose. Neonicotinoids and metabolites were overall detected in 56.5% of urine samples with a median concentration being 0.73 μg g-1 creatinine. Four neonicotinoids or metabolites were detected in more than 10% of urine samples, including N-desmethyl-acetamiprid (47.5%), clothianidin (15.5%), thiamethoxam (16.0%), and imidacloprid (10.5%). Annual household income, family smoking, and pre-pregnancy body mass index were associated with the detection frequencies of neonicotinoids. Pregnant women with a higher consumption frequency of wheat, rice, fresh vegetable, fresh fruit, beef and mutton, fresh milk, yoghourt, candy and chocolate, or carbonated drinks had a higher detection frequency of neonicotinoids. Both HQ and HI were less than one. There was an evident exposure to neonicotinoids in Tibetan pregnant women with both plant- and animal-derived food items as exposure sources, but a low health risk was found based on current safety thresholds.

Association between maternal urinary neonicotinoid concentrations and child development in the Japan Environment and Children's Study

BACKGROUND

Recent studies have reported the effect of neonicotinoid (NEO) exposures on development in human. However, information about the risk of childhood development delays due to NEO exposures is limited.

OBJECTIVES

The study aimed to examine the association between NEO exposure and child development up to 4 years of age using data of the Japan Environment and Children's Study.

METHODS

The study employed urinary NEO and metabolite concentrations in the first and second or third trimesters; the Japanese translation of the Ages and Stages Questionnaire (third edition; J-ASQ-3) scores on developmental delay in five domains, namely communication, gross motor skills, fine motor skills, problem solving, and personal-social characteristics from 6 months to 4 years of age; and self-reported questionnaire data. The associations between urinary NEO concentrations and J-ASQ-3 results were analysed using the treed distributed lag mixture model. A total of 8538 participants were included in statistical analyses.

RESULTS

The determination rates of urinary acetamiprid-N-desmethyl (dm-ACE), clothianidin (CLO), dinotefuran (DIN) and thiamethoxam (THX) were greater than 50%. Median urinary dm-ACE, CLO, DIN and THX concentrations were 0.34, 0.14, 0.22 and 0.05 ng/ml, respectively, in samples collected during gestational weeks < 23, and 0.28, 0.12, 0.18 and 0.04 ng/ml, respectively, in those collected during gestational weeks ≥ 23. The binomial scores divided by the cut-off values of the J-ASQ were used in the treed distributed lag mixture model. The highest percentage for a domain with a value less than the cut-off value was 'problem solving' at 6 months of age among all the J-ASQ-3 scores (10.5%). There was no statistically significant association between maternal urinary dm-ACE, CLO, DIN and THX concentrations during pregnancy and the J-ASQ-3 results up to 4 years of age. Objective assessment of child development in different populations may be warranted to confirm our findings.

Study on the Relationship Between Serum Iodine and Thyroid Dysfunctions: a Cross-Sectional Study

The relationship between serum iodine (SIC) and thyroid dysfunctions in adults is poorly understood, and this study aimed to explore their relationship. A total of 1320 participants were included in the final analysis. We collected basic demographic information, blood, and spot urine samples to determine serological indices and iodine nutritional status. The median (IQR) of urinary iodine (UIC)/urinary creatinine (UCr), UIC, SIC were 138.1 (91.1, 207.6) μg/g, 155.8 (94.5, 211.1) μg/L, and 70.6 (59.8, 83.9) μg/L, respectively. The 90% reference ranges for UIC/UCr and SIC were 66.5-349.8 mg/g and 49.3-97.1 μg/L. SIC was positively correlated with UIC and UIC/UCr. The prevalence of overt hypothyroidism and subclinical hypothyroidism in female was significantly higher than that in male (P = 0.02, P = 0.002). In male, subjects above the upper reference value of SIC (97.1 μg/L) had a higher risk of subclinical hyperthyroidism (OR = 4.46, 95% CI: 1.29, 12.8) and overt hypothyroidism (OR = 5.59, 95% CI: 1.88, 6.42). In female, subjects below the lower reference value of SIC (49.3 μg/L) had a higher risk of overt hypothyroidism (OR = 2.18, 95% CI: 1.10, 4.06), TgAb positive (OR = 1.97, 95% CI: 1.15, 3.32) and TPOAb positive (OR = 2.48, 95% CI: 1.41, 4.26). In conclusion, serum iodine can be used as an indicator to evaluate iodine nutritional status and thyroid dysfunctions. Higher serum iodine concentration was associated with an increased risk of subclinical hyperthyroidism and overt hypothyroidism in men; lower serum iodine concentration was associated with an increased risk of overt hypothyroidism and positive TgAb and TPOAb in women.

Exposure of Tibetan pregnant women to antibiotics in China: A biomonitoring-based study

Tibetan people are one Chinese ethnic minority living in Qinghai-Tibet Plateau with an average altitude of more than 4500 m. High altitude could cause a different antibiotic exposure, but relevant information is limited in Tibetan people. We investigated 476 Tibetan pregnant women in Lhasa, Tibet in 2021 and measured 30 antibiotics from five categories in urine, including 13 veterinary antibiotics (VAs), five human antibiotics (HAs), and 12 human/veterinary antibiotics (H/VAs). Food consumption was investigated by a brief food frequency questionnaire. Health risk was assessed by hazard quotient (HQ) and hazard index (HI) based on acceptable daily intakes (ADIs). All antibiotics were overall detected in 34.7% of urine samples with the 75th percentile concentration of 0.19 ng/mL (0.35 μg/g creatinine). HAs, VAs, and H/VAs were respectively detected in 5.3%, 13.0%, and 25.0% of urine samples, with the 95th percentiles of 0.01 ng/mL (0.01 μg/g creatinine), 0.50 ng/mL (0.99 μg/g creatinine), and 3.58 ng/mL (5.02 μg/g creatinine), respectively. Maternal age, smoking of family members, and housework time were associated with detection frequencies of HAs, VAs, or sum of all antibiotics. Pregnant women with a more frequent consumption of fresh milk, egg, yoghourt, poultry meat, and fish had a higher detection frequency of VAs or H/VAs. Only ciprofloxacin and tetracycline had a HQ of larger than one based on microbiological effect in 1.26% and 0.21% of pregnant women, respectively and a HI of larger than one was found in 1.47% of pregnant women. The findings suggested that there was an evident antibiotic exposure from various sources in Tibetan pregnant women with some basic characteristics of pregnant women as potential predictors and several animal-derived food items were important sources of exposure to antibiotic with a fraction of pregnant women in the health risk related to microbiological disruption of gut microbiota.

Benchmark dose in the presence of coexposure to melamine and diethylhexyl phthalate and urinary renal injury markers in pregnant women

Environmental exposures to mixtures of toxic chemicals have potential interaction effects that may lead to hazard index values exceeding one. However, current regulation levels, such as tolerable daily intake (TDI), are mostly based on experimental studies conducted with a single chemical compound. In this study, we assessed the relationships between melamine and di-(2-ethylhexyl) phthalate (DEHP) exposure and their coexposure with the early renal injury markers N-acetyl -D-glucosaminidase (NAG), albumin/creatinine ratio (ACR), and microalbuminuria in 1236 pregnant women. Various generalized linear models with interaction terms and Bayesian kernel machine regression models were used for the (co-)exposure response associations. We derived the benchmark dose (BMD) and the corresponding one-sided 95% confidence bound BMDL based on the estimated (covariate-adjusted) average daily intake of melamine and DEHP metabolites measured in spot urine of the women collected during the third trimester. Given a benchmark response of 0.1, the BMDL level of melamine (DEHP) exposure on NAG (ACR, microalbuminuria) was 2.67 (11.20, 4.45) μg/kg_bw/day, and it decreased to as low as 1.46 (3.83, 2.73) μg/kg_bw/day when considering coexposure to DEHP (melamine) up to the 90th percentile. Both the exposure threshold levels of melamine and DEHP for early renal injuries in pregnant women were several-fold to one order lower than the current recommended TDIs by the WHO and the US FDA and EPA and were even lower considering coexposure. Because of concurrent exposures in real-world environments, more stringent regulation levels are recommended in susceptible populations, such as pregnant women, due to potential synergistic mixture effects.

Pregnant Dutch Women Have Inadequate Iodine Status and Selenium Intake

Iodine and selenium are essential for thyroid hormone synthesis. Iodine and selenium interact. Pregnancy increases the maternal iodine requirement. We previously reported inadequate iodine status in pregnant Dutch women. Since little is known about their selenium intake, we investigated the iodine status and selenium intake in relation to iodine and selenium supplement use during pregnancy. Iodine status was established in 201 apparently healthy pregnant women as 24 h iodine excretion (24H-UIE; sufficient if median ≥225 µg), iodine concentration (24H-UIC; ≥150 µg/L) and iodine/creatinine ratio (24H-UICR; ≥150 µg/g). Selenium intake was calculated from 24 h selenium excretion. Iodine status in pregnancy proved insufficient (medians: 24H-UIE 185 µg; 24H-UIC 95 µg/L; 24H-UICR 141 µg/g). Only women taking 150 µg iodine/day were sufficient (median 24H-UIE 244 µg). Selenium intake was below the Estimated Average Requirement (EAR; 49 µg/day) in 53.8%, below the Recommended Dietary Allowance (RDA; 60 µg/day) in 77.4% and below the Adequate Intake (AI; 70 µg/day) in 88.7%. Combined inadequate iodine status and selenium intake <RDA was found in 61%. Women who want to become pregnant should, consistently with WHO and ETA recommendations, be advised to use a 150 µg iodine-containing supplement. Concomitant selenium supplementation should be added to this advice, at least in The Netherlands.

Evaluation of iodine nutritional status during pregnancy by estimated 24-h urinary iodine excretion: population variation range and individual accuracy

Objective:

To explore the accuracy of estimated 24-h urinary iodine excretion (24-h UIE_est) in assessing iodine nutritional status.

Design:

Fasting venous blood, 24-h and spot urine samples were collected during the day. The urinary iodine concentration (UIC) and urinary creatinine concentration (UCrC) were measured, and the urinary iodine-to-creatinine ratio (UI/Cr), 24-h UIE_est, and 24-h urinary iodine excretion (24-h UIE) were calculated. At the population level, correlation and consistency between UIC, UI/Cr, 24-h UIE_est and 24-h UIE were assessed using correlation analysis and Bland–Altman plots. At the individual level, receiver operating characteristic (ROC) curves were used to analyse the accuracy of the above indicators for evaluating insufficient and excessive iodine intake. The reference interval of 24-h UIE_est was established based on percentile values.

Setting:

Indicator can accurately evaluate individual iodine nutrition during pregnancy remains controversial.

Participants:

Pregnant women (n 788).

Results:

Using 24-h UIE as standard, the correlation coefficients of 24-h UIE_est from different periods of the day ranged from 0·409 to 0·531, and the relative average differences ranged from 4·4 % to 10·9 %. For diagnosis of insufficient iodine intake, the area under the ROC curve of 24-h UIE_est was 0·754, sensitivity and specificity were 79·6 % and 65·4 %, respectively. For diagnosis of excessive iodine intake, the area of 24-h UIE_est was 0·771, sensitivity and specificity were 66·7 % and 82·0 %, respectively. The reference interval of 24-h UIE_est was 58·43–597·65 μg.

Conclusions:

Twenty-four-hour UIE_est can better indicate iodine nutritional status at a relatively large sample size in a given population of pregnant women. It can be used for early screening at the individual level to obtain more lead time for pregnant women.