Analysis of spot urine biomarkers and association with body weight in Japanese elementary schoolchildren.

Childhood obesity is rapidly increasing worldwide and is largely the consequence of adoption of unhealthy diets excessive in calories and salt (NaCl) as well as devoid in pivotal micronutrients such as potassium (K) and magnesium (Mg). Education-based programs aiming to encourage healthy food knowledge and behaviors are crucial at a young age, and for this purpose, convenient ways to assess daily dietary intake are warranted. We therefore attempted to evaluate the dietary intake of Okinawan schoolchildren in Japan by analyzing a series of biomarkers in morning spot urine samples and explore whether these biomarkers correlate with body weight and a series of metabolic parameters. We enrolled 98 third-grade elementary schoolchildren in Okinawa, Japan. Morning spot urine samples were collected and analyzed using high-performance liquid chromatography (HPLC) to assess dietary intake. We found that estimated daily NaCl intake was higher in obese/overweight children as compared to healthy-weight children (p = 0.0001). There was also a significant positive correlation between body mass index (BMI) and NaCl intake (Spearman) (ρ = 0.45, p < 0.0001) and a negative correlation between BMI and Mg/Cr (ρ = -0.27, p = 0.01). Furthermore, Na/K ratio was higher in samples collected on Monday (weekend) as compared to samples collected on Thursday or Friday (weekday) (p < 0.0001). CONCLUSION: Via the use of morning spot urine analyses, our results show that NaCl intake was associated with obesity, and Mg excretion negatively correlated with BMI in Japanese schoolchildren, highlighting the potential role of these micronutrients in maintaining a healthy body weight. WHAT IS KNOWN: •Overweight and obesity are largely due to excessive consumption of calories and positively correlated with salt (NaCl) intake. •Spot urine methods are convenient for assessing the nutritional needs and targeting prevention programs in children. WHAT IS NEW: •Utilizing morning spot urine analyses, estimated NaCl intake is positively correlated and Mg/Cr negatively correlated with BMI in Okinawan schoolchildren. •As estimated via morning spot urine samples, a greater proportion of children likely exceeds the recommended NaCl intake on the weekend as compared to weekday.

Retrospective exploratory analyses on gender differences in determinants for incidence and progression of diabetic retinopathy in Japanese patients with type 2 diabetes mellitus.

Gender differences in risks for macrovascular complications in type 2 diabetes mellitus (T2DM) have been well established. However, the impact of gender differences on diabetic retinopathy (DR) has not been fully elucidated. We therefore retrospectively explored gender-specific determinants for DR in patients with T2DM in a small sized Japanese cohort in Okinawa. There were 214 patients who were diagnosed as no DR (n = 142) and non-proliferative DR (n = 72) in 2009. During the follow-up of median 7 years, 41/142 of incidence, 26/72 of progression, and 67/214 of incidence and progression were observed, respectively. DR was assessed using the modified international clinical DR severity scales. The risks for incidence, progression as well as incidence and progression of DR were comparable between men and women, respectively. Cox proportional hazard models in multivariate analyses demonstrated that the only common determinant in both men and women for DR was the duration of T2DM. Regarding gender-specific determinants, lower level of serum albumin in men as well as higher HbA1c, lower level of estimated glomerular filtration rate, and lower level of serum uric acid in women were extracted, respectively. Although precise mechanisms for such gender-specific determinants of DR still remain unsolved, the present study would highlight a couple of factors associated with gender-specific determinants for DR in a limited numbers of Japanese cohort. Prospective observational studies on gender-specific determinants of DR in a large scale cohort are warranted to further clarify underlying mechanisms.