The nutritional profile of commercial complementary foods in Japan: comparison between low- and high-price products.

Despite the increasing market share of commercial complementary foods, their nutritional characteristics and those associated with the price of products are still unknown in Japan. We compared the nutritional characteristics of commercially available complementary foods of different price levels in Japan. Data were obtained from the websites of Japanese brands of infant and young children's food. Nutrient profiles (unit/100 g), ingredients and food additives were compared between low- and high-priced products by product type. Sixty-three dry meals, 425 soft meals, 187 snacks and sweets, and 60 drinks were analysed. One-fifth of meals and snacks exceeded the CODEX-defined limit (200 mg Na/100 g). Most products lacked content information on nutrients non-mandated to be indicated. High-priced soft meals contained more protein (2·5 v. 1·9 g/100 g) and less Na (0·18 v. 0·46 g/100 g), less frequently used ≥ 1 added sugar (23 % v. 82 %), and less frequently used food additives than low-priced products; however, they had a lower variety of ingredients. The prevalence of products containing ≥ 1 added sugar was higher in low-priced snacks and sweets (91 % v. 77 %) but lower in drinks (48 % v. 84 %) than in their high-priced counterparts. High Na content is a concern among commercial complementary foods in Japan. Nonetheless, the relationship between the price and nutritional profile of these foods differs by product type. High-priced soft meals might be more favourable regarding nutrient content but not the variety of ingredients than low-priced counterparts. These findings elucidate the nutritional characteristics of commercial complementary foods in Japan.

Characteristics of women who dropped out from pregnancy register in Okinawa, Japan: Findings from a retrospective cohort study.

AIM: There is little evidence regarding women who cannot register live births after pregnancy. We aimed to clarify the difference in baseline characteristics between women who registered live births and those who did not (i.e., dropout). METHODS: We assessed the birth cohort data of 1976 Japanese women who registered their pregnancies between July 2013 and March 2014 in Naha and Urasoe City, Okinawa, Japan. The database consisted of anthropometric data, reproductive history, sociodemographic characteristics, and dietary intake. We estimated the prevalence ratio to examine the associations of baseline characteristics with dropout by multivariable-adjusted Poisson regression with robust standard error estimation. RESULTS: We identified 272 dropouts (13.8%) in the pregnancy registry. About 15% of women reported experience of alcohol drinking preceding 1 month of pregnancy registration. Most participants' vitamin B1 (92.1%) and folate (74.7%) consumption was inadequate considering the dietary reference intake for Japanese pregnant women, but it was not associated with a high prevalence of dropout. The prevalence of dropout was significantly higher in teenagers (prevalence ratio [PR] = 2.06, 95% confidence interval [CI] 1.38-3.07) and early 20s (PR = 1.42, 95% CI 1.04-1.93) than in women in late 20s. In addition, alcohol consumption was potentially associated with a high prevalence of dropout (adjusted prevalence ratio [aPR] = 1.31, 95% CI 0.99-1.73). Participants who experienced one or more live births (aPR = 0.43, 95% CI 0.28-0.66) were less likely to dropout. CONCLUSION: We found that the potential risk factors for dropout from pregnancy registration were young maternal age, no childbirth experience, and alcohol consumption.

Snacking in Japanese nursery school children aged 3-6 years: its characteristics and contribution to overall dietary intake.

OBJECTIVE: This cross-sectional study evaluated the dietary characteristics of snacks, the contribution of snacks to daily nutrient intake and the association of energy intake (EI) from snacks with the prevalence of nutritional inadequacy in Japanese nursery school children. DESIGN: Foods and nutrients consumed in each eating occasion were assessed by 3-d dietary records. The prevalence of inadequate intake of twenty nutrients assessed by the age- and sex-specific reference values in the Japanese Dietary Reference Intakes was compared according to tertile categories of EI from snacks. SETTING: A multi-regional dietary survey based on nursery schools in Japan. PARTICIPANTS: A total of 187 boys and 191 girls aged 3-6 years. RESULTS: EI from snacks accounted for 19·5 % (sd 6·9) of total daily EI. Confectionaries accounted for the largest part of EI from snacks (35·3 %), followed by milk (19·5 %). Relative to their energy contribution, snacks accounted for a small proportion for all nutrients examined, except for free sugar, calcium, SFA and riboflavin. Although a higher EI from snacks was associated with favourable profiles for intakes of calcium, iron, thiamine and riboflavin, excessive intakes of free sugar and Na were more prevalent among children with a higher EI from snacks. CONCLUSIONS: Although snacks are effective in meeting the requirement of some nutrients among Japanese nursery school children, snacks are generally not nutrient-dense and have an impact on excessive intake of some nutrients. There is hence room for improvement in food choices at snack time.

Association of Free Sugar Intake Estimated Using a Newly-Developed Food Composition Database With Lifestyles and Parental Characteristics Among Japanese Children Aged 3-6 Years: DONGuRI Study.

BACKGROUND: The lack of comprehensive food composition databases for sugar contents in Japanese foods has led to the lack of nutritional epidemiologic studies on sugar intake in Japanese population. This cross-sectional study aimed to investigate the association of free sugar intake estimated using a newly developed food composition database with the characteristics and lifestyles of Japanese children aged 3-6 years. METHODS: The food composition database contained information on sugars in 2,222 commonly consumed Japanese foods. Using this database, we estimated the sugar (total, added, and free sugars) intakes derived from a 3-day weighed dietary record of 166 boys and 166 girls aged 3-6 years living in 24 prefectures in Japan. RESULTS: The mean free sugar intake was 26.8 g/d (standard deviation [SD], 12.3 g/d), while the mean value for energy intake was 7.8% (SD, 3.2%). The prevalence of excessive free sugar intake (≥10% of energy intake) was 21.7%. Among the characteristics and lifestyles examined, screen time was most strongly associated with the prevalence of excessive free sugar intake: multivariate adjusted odds ratios for screen time <0.5, ≥0.5 to <1, and ≥1 h/d were 1.0 (reference), 3.81 (95% confidence interval, 1.04-13.98), and 4.36 (95% confidence interval, 1.16-16.35), respectively. Additionally, younger age, shorter sleep, and mothers with office work and service and sales jobs (compared with those with professional and managerial jobs) were significantly associated with a higher prevalence of excessive free sugar intake. CONCLUSIONS: This study showed the sugar intake of Japanese children aged 3-6 years is positively associated with screen time.

Nutritional quality of meals offered to children (kids' meals) at chain restaurants in Japan.

OBJECTIVE: To evaluate the nutritional quality, particularly the fat and salt contents, of meals offered to children (kids' meals) at chain restaurants in Japan. DESIGN: A web-based content analysis was conducted to evaluate the type of restaurant, type of meal, incentives, health claims and nutrition data of kids' meals. The nutritional appropriateness of kids' meals was assessed with the Standard for the School Lunch Program, which regulates energy (≤2218 kJ), protein (20-30 g), fat (≤30 % of energy (E%)) and salt (<2 g) contents of the school lunch in Japan. Linear mixed models were employed for evaluating the relationship between the characteristics of kids' meals and their fat (E%) or salt (g) content. SETTING: Restaurant websites providing nutritional data of kids' meals in Japan. SUBJECTS: A total of 438 kids' meals offered by forty-two chain restaurant brands from across twenty food-service companies. RESULTS: Overall, 58·9, 40·6 and 34·5 % of the kids' meals were determined to be appropriate regarding their energy (≤2218 kJ), fat (≤30 E%) and salt content (<2 g). In addition, 15·5 % of kids' meals met the multiple standards of energy, fat and salt contents. 'Japanese-style' (restaurant-level characteristic) was associated with a decrease in the fat E% of kids' meals (ß=-6·2; 95 % CI -11·0, -1·4) and an increase in the salt content (ß=0·7; 95 % CI 0·06, 1·3). CONCLUSIONS: The characteristics of the restaurant-served kids' meals in Japan were high fat E% and high salt content from different cultural contexts of the Western and the Japanese diet.

Urine 24-Hour Sodium Excretion Decreased between 1953 and 2014 in Japan, but Estimated Intake Still Exceeds the WHO Recommendation.

Background: Accurate monitoring of sodium intake is necessary for evaluating strategies used to reduce sodium intake. However, no repeat survey has been conducted in representative populations in Japan to examine trends in sodium intake with the use of 24-h urinary sodium excretion, a standard evaluation method for sodium intake monitoring.Objective: The objective of this study was to examine potential trends in sodium intake by examining previous reports of 24-h urinary sodium excretion in healthy Japanese adult populations.Methods: We systematically searched for reports of 24-h urinary sodium excretion in healthy Japanese adult populations (mean age range: 18-69 y). We searched PubMed and Web of Science for English-language articles and hand-searched 7 Japanese scientific journals for Japanese-language articles. Trends in urinary sodium excretion were examined with the use of weighted linear regression and random-effects meta-regression analyses, with adjustment or stratification to address study characteristics (population mean age, percentage of men, and sample size) and study assessment for completeness of urine collection.Results: We identified 68 reports of urinary sodium excretion from 53 articles published from 1953 through 2014 that showed high rates of urinary sodium excretion in healthy Japanese adult populations (weighted mean: 4900 mg/d). The rate of urinary sodium excretion significantly decreased between 1953 and 2014, by 4350 mg/d (P < 0.001); however, the rate of reduction in urinary sodium excretion was variable and decreased with time (P-linear trend <0.001 and P-quadratic trend <0.001). In the random-effects meta-regression analysis of studies that assessed completeness of urine collection with creatinine excretion, no significant relation between urinary sodium excretion and year was observed from 1978 to 2014 (ß = -16, P = 0.40).Conclusion: Despite a decrease in urinary sodium excretion in healthy Japanese adult populations between 1953 and 2014, sodium intake still exceeds the WHO recommendation for adults. This review was registered at PROSPERO as CRD42016035452.

Iodine Excretion in 24-hour Urine Collection and Its Dietary Determinants in Healthy Japanese Adults.

BACKGROUND: Since seaweed is a common component of the Japanese diet, iodine intake in Japanese is expected to be high. However, urinary iodine excretion, measured using 24-hour urine samples, and its dietary determinants are not known. METHODS: Apparently healthy adults aged 20 to 69 years living in 20 areas throughout Japan were recruited in February and March, 2013. Urinary iodine excretion was evaluated using 24-hour urine collected from 713 subjects (362 men and 351 women), and the difference among age groups was assessed. The association between dietary intake of food groups and urinary iodine excretion was assessed among 358 subjects who completed a semi-weighed 4-day diet record (DR) and urine collection. The correlations between iodine intake and iodine excretion were also evaluated, and correlation coefficients were calculated for iodine intake in the DR of the overlapping day or the DR 1 day before and after urine collection. RESULTS: Median iodine excretion in 24-hour urine was 365 µg, and excretion was significantly higher in older subjects. Iodine intake estimated by the DRs was significantly correlated with urinary iodine excretion when DRs and urine collection were obtained on the same day (r = 0.37). After adjustment for confounding factors, iodine excretion was significantly associated with intakes of kelp and soup stock from kelp and fish. CONCLUSIONS: Although multiple measurements for urinary iodine are required to confirm our results, this study showed the current iodine status of healthy Japanese adults. The results suggest that kelp and fish are the main contributors to Japanese iodine status measured by 24-hour urine.

Sodium sources in the Japanese diet: difference between generations and sexes.

OBJECTIVE: Globally, the Na consumption of most people exceeds the WHO recommendation. To be effective, salt reduction programmes require assessment of the dietary sources of Na. Due to methodological difficulties however, comprehensive assessments are rare. Here, we identified Na sources in the Japanese diet using a 4 d diet record that was specifically designed for Na source description. DESIGN: A cross-sectional study. SUBJECTS: Apparently healthy men (n 196) and women (n 196) aged 20-69 years. SETTING: The subjects were recruited from twenty-three of forty-seven prefectures in Japan. RESULTS: The proportion of discretionary Na intake in total Na intake was 52·3 % in men and 57·1 % in women, and was significantly lower in younger subjects. The two major food groups contributing to Na intake were seasonings such as salt or soya sauce (61·7 % of total Na intake in men, 62·9 % in women) and fish and shellfish (6·7 % in men, 6·6 % in women). The third major contributor differed between men and women (noodles in men, 4·9 %; bread in women, 5·0 %). Further, the contribution of each food group to total Na intake differed among age groups. CONCLUSIONS: While individual efforts to decrease Na intake remain important, population approaches to reducing Na content in processed foods are already equally important and will assume greater importance in the future even in Japan, an Asian country facing a rapid Westernization in dietary habits.

Dietary patterns extracted from the current Japanese diet and their associations with sodium and potassium intakes estimated by repeated 24 h urine collection.

OBJECTIVE: To identify dietary patterns in the current Japanese diet and evaluate the associations between these patterns and Na and K intakes. DESIGN: Dietary patterns were extracted by factor analysis from the intakes of food groups assessed with a validated self-administrated diet history questionnaire. Na and K intakes and urinary Na:K were assessed by repeated 24 h urine collection. SUBJECTS: Healthy Japanese adults aged 20-69 years (353 men and 349 women). SETTING: Twenty study areas in twenty-three prefectures in Japan. Result Four dietary patterns were identified in each sex. After adjustment for several confounding factors, the 'Fish and vegetable' pattern was associated with higher urinary Na excretion, but the association was not significant (P=0·37 in men and P=0·06 in women). This pattern was also associated with higher K excretion in both sexes. The 'Noodle' pattern tended to be associated with higher urinary Na excretion (P=0·17 in men and P=0·04 in women) and higher Na:K (P=0·02 in men). The 'Meat, vegetable and oil' (in men)/'Meat and oil' (in women) and 'Bread and confectioneries' patterns were not associated with urinary Na excretion (in men) or were negatively associated (in women). CONCLUSIONS: Contrary to the case in Western countries, the 'Fish and vegetable' and 'Noodle' patterns contributed to higher Na intake in Japan. Target foods for salt reduction should be set based on careful consideration of the relationships between dietary patterns and Na and K intakes in the target population.

Adequacy of iodine intake in three different Japanese adult dietary patterns: a nationwide study.

BACKGROUND: Iodine intake is considered to be high in Japan due to regular seaweed consumption. Subgroups that do not have a traditional Japanese-style diet may consume insufficient amounts of iodine. METHOD: Three hundred and ninety apparently healthy adults (195 men and 195 women) aged 20 to 69 years from 20 areas throughout Japan completed four-day diet records and collected a 24-h urine sample. Dietary patterns were extracted from 31 food groups by cluster analysis. The iodine adequacy of each dietary pattern was examined using reference values from the Dietary Reference Intakes for Japanese. RESULTS: Three dietary patterns, labelled "Cluster I (Rice and vegetables)" (n = 101), "Cluster II (Meat, non-Japanese noodles, and sugar-sweetened beverages)" (n = 34), and "Cluster III (Fish, Japanese noodles, and alcohol)" (n = 60), were identified in male subjects. Another set of three patterns, "Cluster I (Rice and vegetables)" (n = 22), "Cluster II (Fish and Japanese noodles)" (n = 33), and "Cluster III (Bread and non-Japanese noodles)" (n = 140), was found in female subjects. Although the habitual iodine intake of almost all participants was above the estimated average requirement (EAR), iodine intake was statistically significantly lowest in Cluster II in men and Cluster III in women. Moreover, the mean participant age was the youngest in these clusters. CONCLUSION: Although Japan is known as a high iodine-consuming country, some Japanese individuals who do not eat a traditional Japanese-style diet consume low amounts of iodine. Since younger people tend to have modern, Westernized dietary patterns, iodine deficiency might be given additional consideration hereafter in Japan.

Estimation of sodium and potassium intakes assessed by two 24 h urine collections in healthy Japanese adults: a nationwide study.

Excess Na intake and insufficient K intake are well-known risk factors for CVD. International comparative studies have reported that Japan has the highest intake of Na and the lowest intake of K in the world. However, no recent study has precisely assessed Na and K intakes in Japanese adults. In the present study, Na and K intakes were estimated from two 24 h urine collections implemented in twenty-three out of forty-seven prefectures in Japan. Apparently healthy men (n 384) and women (n 376), aged 20 to 69 years, who had been working in welfare facilities were recruited, with data collection conducted in February and March 2013. The mean Na excretion was 206·0 mmol/d in men and 173·9 mmol/d in women. The respective values of K excretion were 51·6 and 47·2 mmol/d. The excretion of both Na and K varied considerably among the prefectures, and was higher in subjects with a higher BMI. In contrast, only K excretion was associated with age. After estimating the usual intakes of Na and K, it was found that none of the male subjects met the recommended Na intake values of the WHO, and that only 3·2 % met those of the Japanese government. The respective values for females were 0·1 and 5·0 %. For K intake, 7·5 % of the total subjects met the recommended values of the WHO and 21·7 % met those of the Japanese government. These findings suggest that there is an urgent need for the development of an effective intervention programme to reduce Na intake and promote K intake in the Japanese population.

Formulas developed based on the ratio of urea nitrogen to creatinine concentrations obtained from multiple spot urine samples are acceptable to predict protein intake at group level but not at individual level.

In this study, we hypothesized that spot urine can be used to predict protein intake at both group and individual levels. Participants (n = 369) of this study were recruited from all 47 prefectures in Japan. Sex-specific formulas were developed based on the ratio of urea nitrogen to creatinine concentration obtained from 3 spot urine samples. Validity of the formulas was examined against two 24-hour urine collections for 7 combinations of spot urine (single and means of 2 or 3 samples) using t test (mean estimation), Spearman correlation, and Bland-Altman plot (individual bias). Means of measured protein intake based on 24-hour urinary excretions were 87.3 g/d (standard deviation 19.7) for men and 70.5 g/d (standard deviation 14.7) for women. Irrespective of sex, the predicted intakes were not significantly different (within 2.7% of differences) from those measured by urinary excretions. Predicted intakes were moderately correlated with measured intakes (men, 0.45-0.60; women, 0.35-0.53). Even after using the mean of 3 samples, Bland-Altman plots showed a considerably wide limit of agreement (men, -30 to 33 g/d; women, -27 to 24 g/d). Except for using single spot urine samples in women, the formula tended to overestimate intake at a lower and underestimate at a higher level of protein intake (slope: men, -0.47 [P < .0001]; women, -0.38 [P = .002]). In conclusion, predictive formulas developed in this study can be used to predict protein intake at group level or to rank individuals' intake but not to predict absolute intake at individual level.

Dietary phosphorus intake estimated by 4-day dietary records and two 24-hour urine collections and their associated factors in Japanese adults.

BACKGROUND/OBJECTIVES: Both self-reported dietary information and urinary excretion have limitations in the assessment of phosphorus intake. We conducted a cross-sectional study to estimate dietary phosphorus intake by dietary records (DR) and 24-h urine collections (UC) and examined associated factors. SUBJECTS/METHODS: A total of 161 men and 161 women aged 20-69 years completed a 4-day DR and two 24-h UC. Phosphorus intake by UC was estimated using the mean phosphorus absorption rate of 14 papers. Associations between phosphorus intake and urinary excretion and age, body mass index (BMI), physical activity, education, and smoking status were examined using multiple linear regression. RESULTS: Phosphorus intake estimated by UC was higher than that estimated by DR (mean: 1393 vs. 1176 mg/day, P < 0.0001 in men; 1082 vs. 1021 mg/day, P = 0.008 in women). Values were significantly correlated (r = 0.29, P = 0.0002 in men; r = 0.30, P = 0.0001 in women). Phosphorus intake estimated by DR was positively associated with age in women. Male current smokers consumed less phosphorus than never smokers. Higher urinary phosphorus excretion was associated with higher BMI in both sexes and higher physical activity in women. CONCLUSIONS: This study showed dietary phosphorus intakes estimated by 4-day DR and by 2-day UC in adults. Although dietary phosphorus intake estimated by DR showed moderate correlation with that by UC, they differed in their association with age, BMI, physical activity, and smoking status.

Estimation of Starch and Sugar Intake in a Japanese Population Based on a Newly Developed Food Composition Database.

Due to a lack of a food composition database on starch and sugars, we developed a comprehensive database on starch and seven types of sugars in commonly consumed foods (n = 2222) in Japan. Dietary record data of 368 toddlers (aged 18⁻35 months), 376 preschool children (aged 3⁻6 years), 915 schoolchildren (aged 8⁻14 years) and 392 adults (aged 20⁻69 years) were used. The mean starch intake ranged from 55.6 g/day (female toddlers) to 206.0 g/day (male schoolchildren). Irrespective of age and sex, >50% of starch was provided by rice and grains. The mean total sugar intake ranged from 46.1 g/day (female toddlers) to 68.7 g/day (male schoolchildren). In all age and sex groups, the major contributors of total sugar included sucrose (mean: 18.2⁻34.0 g/day), glucose (7.8⁻13.1 g/day), lactose (5.3⁻13.1 g/day) and fructose (7.6⁻11.1 g/day). The top food sources were dairy products (toddlers) and confectionaries (other age groups) for total sugar, confectionaries for sucrose, fruits (toddlers) and vegetables (other age groups) for glucose, dairy products for lactose and fruits (toddlers and preschool children) and vegetables (schoolchildren and adults) for fructose. In conclusion, this study clarified the starch and sugar intake in Japan and provides a foundation for future research.

Adequacy of Usual Intake of Japanese Children Aged 3⁻5 Years: A Nationwide Study.

We assessed the adequacy of nutrient intakes of Japanese children aged 3⁻5 years. Dietary information was collected using a 3-nonconsective-day weighed dietary record among 143 boys and 143 girls. Estimates of usual nutrient intakes from foods and beverages were obtained using the best-power method. The proportions of children with intakes below and above the Japanese Dietary Reference Intakes (DRIs) were estimated. The estimated usual intakes of boys and girls were adequate for most nutrients, given the low proportion (≤2%) of children consuming diets that fell below the Estimated Average Requirement (EAR) or the mean usual intakes higher than the Adequate Intake. However, a high percentage of boys and girls had usual intakes below the EAR for calcium (64% and 54%, respectively), vitamin A (20% and 11%, respectively), thiamin (15% and 41%, respectively), and iron (27% and 10%, respectively). Additionally, 62% of boys and 66% of girls had diets that exceeded the recommended range for total fat (20%⁻30% energy). Further, 92% for boys and 85% for girls consumed diets that exceeded the recommended limit for sodium (4.0 and 4.5 g NaCl equivalent/day, respectively). In conclusion, the estimated usual intakes were adequate for most nutrients in this sample of 3⁻5-year-old Japanese children.

Within-country variation of salt intake assessed via urinary excretion in Japan: a multilevel analysis in all 47 prefectures.

Salt intake in Japan remains high; therefore, exploring within-country variation in salt intake and its cause is an important step in the establishment of salt reduction strategies. However, no nationwide evaluation of this variation has been conducted by urinalysis. We aimed to clarify whether within-country variation in salt intake exists in Japan after adjusting for individual characteristics. Healthy men (n=1027) and women (n=1046) aged 20-69 years were recruited from all 47 prefectures of Japan. Twenty-four-hour sodium excretion was estimated using three spot urine samples collected on three nonconsecutive days. The study area was categorized into 12 regions defined by the National Health and Nutrition Survey Japan. Within-country variation in sodium excretion was estimated as a population (region)-level variance using a multilevel model with random intercepts, with adjustment for individual biological, socioeconomic and dietary characteristics. Estimated 24 h sodium excretion was 204.8 mmol per day in men and 155.7 mmol per day in women. Sodium excretion was high in the Northeastern region. However, population-level variance was extremely small after adjusting for individual characteristics (0.8 and 2% of overall variance in men and women, respectively) compared with individual-level variance (99.2 and 98% of overall variance in men and women, respectively). Among individual characteristics, greater body mass index, living with a spouse and high miso-soup intake were associated with high sodium excretion in both sexes. Within-country variation in salt intake in Japan was extremely small compared with individual-level variation. Salt reduction strategies for Japan should be comprehensive and should not address the small within-country differences in intake.

Simple questions in salt intake behavior assessment: comparison with urinary sodium excretion in Japanese adults.

BACKGROUND AND OBJECTIVES: To clarify whether six conventional 'high-risk' behaviors toward excess salt intake captured by simple questions such as frequency of salty food consumption are related to actual salt intake. Also, to examine the relationship of nutrition knowledge, food label use, and food preparation with actual salt intake. METHODS AND STUDY DESIGN: Study participants were 742 subjects (370 men and 372 women) aged 20-69 years from 20 areas of Japan. Salt intake and dietary knowledge/behavior were evaluated with two 24-hour urine collections and a questionnaire, respectively. Multivariable linear regression analyses by sex included sodium excretion as a dependent variable, each knowledge/behavior item as an independent variable, and with age, body mass index, education, and smoking as covariates. RESULTS: Four 'high-risk' behaviors (frequency of miso soup and salty foods consumption, proportion of consumed noodle soup, and amount of seasoning/condiment use) were associated with higher sodium excretion in men (p for trend <=0.04) and were marginally associated in women (p for trend <=0.06). Combination of these behaviors elevated the odds ratios for excess salt intake (sodium excretion: >136 mmol/day). Most of the other nine dietary factors were not associated with sodium excretion. Interestingly, women who decided to purchase foods after referring to the salt/sodium content information on food label, had significant lower sodium excretion than other women (p for trend=0.03). CONCLUSIONS: High-risk behaviors toward excess salt intake captured by simple questions were actually related to excess salt intake. Specific and practical advice based on answers to these questions might contribute to salt reduction in Japanese population.

Advantage of multiple spot urine collections for estimating daily sodium excretion: comparison with two 24-h urine collections as reference.

OBJECTIVE: Several estimation methods for 24-h sodium excretion using spot urine sample have been reported, but accurate estimation at the individual level remains difficult. We aimed to clarify the most accurate method of estimating 24-h sodium excretion with different numbers of available spot urine samples. METHODS: A total of 370 participants from throughout Japan collected multiple 24-h urine and spot urine samples independently. Participants were allocated randomly into a development and a validation dataset. Two estimation methods were established in the development dataset using the two 24-h sodium excretion samples as reference: the 'simple mean method' estimated by multiplying the sodium-creatinine ratio by predicted 24-h creatinine excretion, whereas the 'regression method' employed linear regression analysis. The accuracy of the two methods was examined by comparing the estimated means and concordance correlation coefficients (CCC) in the validation dataset. RESULTS: Mean sodium excretion by the simple mean method with three spot urine samples was closest to that by 24-h collection (difference: -1.62  mmol/day). CCC with the simple mean method increased with an increased number of spot urine samples at 0.20, 0.31, and 0.42 using one, two, and three samples, respectively. This method with three spot urine samples yielded higher CCC than the regression method (0.40). When only one spot urine sample was available for each study participant, CCC was higher with the regression method (0.36). CONCLUSION: The simple mean method with three spot urine samples yielded the most accurate estimates of sodium excretion. When only one spot urine sample was available, the regression method was preferable.