Association between relatively low blood lead levels and urinary δ-aminolevulinic acid concentrations among male workers at a Japanese battery factory.

OBJECTIVES: Whether the known positive association between blood lead (PbB) levels and urinary δ-aminolevulinic acid (ALAU) also exists at relatively low PbB levels (<40 µg/dL) remains unclear. We aimed to investigate this association at lower PbB levels. METHODS: We analyzed data from biannual medical examinations of workers at a Japanese factory from August 2013 to August 2023. We excluded records from female workers and those with missing data, resulting in a dataset consisting of 1396 records from 155 male workers. We employed mixed-effect linear regression models with a random intercept for workers and additional adjustments for age and smoking status. RESULTS: The median PbB level across all the analyzed records was 8 µg/dL (range: 1-31 µg/dL). Significant positive associations were observed between PbB and ALAU, with a 1-unit increase in natural logarithm-transformed PbB corresponding to a 10.0% increase in ALAU (95% CI, 2.7%-17.9%). Categorized PbB analyses showed a 23.8% increase in ALAU (95% CI, 2.7%-49.2%) for PbB levels at 20-24 µg/dL and an 83.1% increase (95% CI, 30.1%-157.7%) for PbB levels ≥25 µg/dL, compared with those <5 µg/dL. The exposure-response curve analysis indicated a plateau followed by an increasing trend. CONCLUSIONS: A positive and nonlinear association between PbB and ALAU levels was observed at relatively low PbB levels.

Association between the number of teeth and incident pre-diabetes among middle-aged adults with periodontal disease: a retrospective cohort analysis of Japanese claims data.

OBJECTIVES: To investigate the association between the number of teeth and the new onset of pre-diabetes. DESIGN: Retrospective cohort study. SETTING: The National Database of Health Insurance Claims and Specific Health Checkups of Japan, which holds information from both the yearly health check-up programme known as the 'Specific Health Checkup' and health insurance claims data. PARTICIPANTS: 1 098 371 normoglycaemic subjects who participated in the Specific Health Checkup programme every year from fiscal year (FY) 2015 to FY 2018 and had dental insurance claims data with a diagnosis of periodontal disease during FY 2016. OUTCOME MEASURES: Incidence of pre-diabetes or diabetes observed at the Specific Health Checkup during FY 2018. RESULTS: Among the participants, 1 77 908 subjects developed pre-diabetes, and 579 developed diabetes at the check-up during the subsequent follow-up year. Compared with the subjects with 26-28 teeth, those with 20-25, 15-19 or 1-14 teeth were associated with an increased likelihood of developing pre-diabetes or diabetes onset with adjusted ORs of 1.03 (95% CI: 1.02 to 1.05), 1.06 (1.03 to 1.09) and 1.07 (1.04 to 1.11), respectively. No clear modifications were observed for age, sex, body mass index or current smoking. CONCLUSIONS: Having fewer teeth was associated with a higher incidence of pre-diabetes. Due to the limitations of this study, however, causality remains undetermined.

Effects of Lactoferrin on Prevention of Acute Gastrointestinal Symptoms in Winter: A Randomized, Double-Blinded, Placebo-Controlled Trial for Staff of Kindergartens and Nursery Schools in Japan.

This study investigated the preventive effects of lactoferrin (LF) on subjective acute gastrointestinal symptoms during the winter in a randomized, double-blinded, placebo-controlled parallel-group comparative trial. The eligible subjects were healthy adults working at kindergartens and nursery schools. We randomized the subjects to the Placebo group (0 mg/day), the Low LF group (200 mg/day), and the High LF group (600 mg/day) for 12 weeks. The prevalence of acute gastrointestinal symptoms was significantly lower in the High LF (13/112 vs. 26/116; p = 0.030) and the Low LF (13/107 vs. 26/116; p = 0.040) groups than in the Placebo group. The adjusted odds ratio for the prevalence of acute gastrointestinal symptoms was 2.78 (95% CI: 1.19-6.47) in the Placebo group compared with the High LF group. LF is useful to prevent acute gastrointestinal symptoms among childcare workers, who mainly consist of women.

Effects of Lactoferrin on Sleep Conditions in Children Aged 12-32 Months: A Preliminary, Randomized, Double-Blind, Placebo-Controlled Trial.

PURPOSE: To investigate preliminarily the effect of lactoferrin (LF)-fortified formula on sleep conditions in children. STUDY DESIGN: A preliminary, randomized, double-blind, placebo-controlled trial. METHODS: Healthy children between the ages of 12 and 32 months who attended nursery schools in Japan were divided into two groups and assigned a placebo or LF (48 mg/day)-fortified formula. Children's sleep conditions were investigated before and after the 13-week intervention using the Japanese Sleep Questionnaire for Preschoolers (JSQ-P). RESULTS: Altogether, 109 participants were randomized. Eight participants were eliminated due to lost to follow-up, withdrawal of consent, and ineligibility, with 101 participants (placebo, n = 48; LF, n = 53) included in the full analysis set (FAS) and used for analysis. Wake-up time, bedtime, and nighttime sleep were comparable between the two groups before and after intervention. The change in total JSQ-P T scores tended to improve in the LF group (placebo vs LF: 0.5 ± 6.5 vs -1.9 ± 6.1, p = 0.074), in particular, morning symptoms significantly improved (grumpy in the morning, hard to wake-up, and hard to get out of bed) (placebo vs LF: 0.8 ± 6.2 vs -1.9 ± 6.2, p = 0.028). A better trend was also observed in the LF group regarding restless legs syndrome (RLS)-motor (rubs feet at night and touches feet at night) (placebo vs LF: 2.3 ± 10.7 vs -0.6 ± 13.5, p = 0.083) and insufficient sleep (stays up more than one hour later the day before a holiday and wakes up more than one hour later on a holiday) (placebo vs LF: 0.1 ± 9.8 vs -1.7 ± 8.8, p = 0.095). No adverse drug reactions were found. CONCLUSION: LF intake may improve sleep condition, especially morning symptoms in children above one year of age.

Effects of Lactoferrin-Fortified Formula on Acute Gastrointestinal Symptoms in Children Aged 12-32 Months: A Randomized, Double-Blind, Placebo-Controlled Trial.

Objective: We investigated the effects of lactoferrin (LF)-fortified formula on acute gastrointestinal and respiratory symptoms in children. Design: Randomized, double-blind, placebo-controlled trial. Setting and subjects: Children aged 12-32 months in Japan. Intervention: Intake of placebo or LF (48 mg/day)-fortified formula for 13 weeks. Primary endpoint: Prevalence of acute gastrointestinal and respiratory symptom. Results: One hundred nine participants were randomized. Eight participants were lost to follow-up, withdrew consent, or were deemed inappropriate for the trial, with 101 participants receiving complete analyses (placebo group, n = 48; LF group, n = 53). Outcomes: The prevalence of acute gastrointestinal symptoms was significantly less in the LF group (22/53 [41.5%]) than in the placebo group (30/48 [62.5%], p = 0.046). The total number of days having acute respiratory symptoms was significantly lower in the LF group (9.0) than in the placebo group (15.0, p = 0.030). Harms: The rate of adverse events was similar between the groups. No adverse drug reactions were found. Conclusions: LF intake decreased the prevalence of acute gastrointestinal symptoms in children aged 12-32 months.

Effects of Lactoferrin on Subjective Skin Conditions in Winter: A Preliminary, Randomized, Double-Blinded, Placebo-Controlled Trial.

OBJECTIVE: To investigate the effects of lactoferrin (LF) on subjective skin conditions in winter. DESIGN: A preliminary, randomized, double-blinded, placebo-controlled trial. SETTING AND SUBJECTS: Healthy adults in Japan. INTERVENTIONS: Intake of placebo, 200 mg, or 600 mg of LF for 12 weeks in winter. ENDPOINTS: Changes in the scores of subjective skin conditions. RESULTS: Three hundred and forty-six subjects were randomized. Nine subjects (placebo, n=0; 200 mg, n=5; 600 mg, n=4) withdrew consent, and 7 subjects (placebo, n=4; 200 mg, n=2; 600 mg, n=1) were lost to follow-up, resulting in 330 for a full analysis set. OUTCOMES: Changes in the scores of moisture were greater in the 600 mg group than in the placebo group. Changes in the scores of moisture were greater in the 200 mg and 600 mg groups, and of texture were greater in the 600 mg group than in the placebo group in female subjects. CONCLUSION: Intake of LF may improve moisture or texture of skin in winter.