Body mass changes and voluntary fluid intakes of elite level water polo players and swimmers.

Calculated sweat rates (measured by body mass changes) and voluntary fluid intakes were monitored in elite level water polo players and swimmers during normal exercise sessions to determine fluid requirements to maintain fluid balance, and the degree of fluid replacement of these athletes. Data were collected from training and competition sessions for male water polo players (n = 23) and training sessions only for swimmers (n = 20 females; n = 21 males). The calculated average sweat rate and fluid intake rate during training sessions for male water polo players was 287 ml/h and 142 ml/h, respectively, with a rate of 786 ml/h and 380 ml/h during matches. During training sessions for male swimmers, the calculated average sweat rate and fluid intake rate per kilometre was 138 ml/km and 155 ml/km, respectively; and for female swimmers, 107 ml/km and 95 ml/km. There was a wide individual variation in fluid intake and sweat loss of both water polo players and swimmers. Dehydration experienced by athletes in this study was less than typically reported for "land-based" athletes. Errors inherent in the technique used in this study are acknowledged and may be significant in the calculation of reported sweat losses and levels of fluid balance in aquatic athletes.

Association between urinary potassium, urinary sodium, current diet, and bone density in prepubertal children.

BACKGROUND: Our understanding of the role of nutrients in bone development in children is limited. OBJECTIVE: We examined the associations between urinary potassium, urinary sodium, usual dietary intake, and bone mineral density (BMD) in prepubertal children. DESIGN: This was a cross-sectional study of 330 boys and girls aged 8 y. Urinary measures were assessed in a single, timed, overnight urine specimen. Usual diet was assessed with a food-frequency questionnaire completed by a parent or guardian. BMD at the femoral neck, lumbar spine, and total body was measured by dual-energy X-ray absorptiometry. RESULTS: Urinary potassium correlated significantly with BMD at all sites (femoral neck: r = 0.20, P < 0.001; lumbar spine: r = 0.19, P = 0.001; total body: r = 0.24, P < 0.001). After adjustment for confounders (primarily lean body mass), this association was lower in magnitude but remained significant at 2 sites with a consistent trend at the third (femoral neck: P = 0.15; lumbar spine: P = 0.046; total body: P = 0.028). Urinary sodium was not associated with BMD at any site. No nutrient or food intake estimate was associated with BMD, although urinary potassium correlated significantly with potassium intake (r = 0.14, P = 0.016) and fruit and vegetable intake (r = 0.12, P = 0.033). CONCLUSIONS: Urinary potassium was associated with both dietary intake and BMD independent of lean body mass in these well-nourished, calcium-replete young children. These findings should be confirmed in further longitudinal studies. Nevertheless, this association is likely to represent dietary intake of potassium and suggests that measurement of urinary potassium is superior to food-frequency questionnaires for assessing potassium intake in this age group.

Maternal diet during pregnancy is associated with bone mineral density in children: a longitudinal study.

OBJECTIVE: To describe the association between maternal diet during the third trimester of pregnancy and bone mass in 8 y-old male and female children. DESIGN: Longitudinal study. SETTING: Southern Tasmania between 1988 and 1996. SUBJECTS: One-hundred and seventy-three 8-y-old male and female children with adequate maternal dietary information taking part in a study of bone mineralization. RESULTS: After adjustment for confounders, femoral neck bone mineral density (BMD) was positively associated with magnesium and phosphorus density of the maternal diet; lumbar spine BMD was positively associated with magnesium, phosphorus and potassium and negatively associated with fat density while total body BMD was positively associated with magnesium, potassium and protein and negatively associated with fat density (all P<0.05). After further adjustment for other significant dietary factors, the only significant remaining associations observed were for phosphorus and fat at the lumbar spine, although the adjusted goodness of fit of the models improved compared to those including one dietary variable. A child in the 'optimal' levels of dietary exposures had significantly higher adjusted BMD at all sites (femoral neck, +5.5%, lumbar spine, +12%, total body, +6.8%). Calcium intake was not associated with BMD at any site, possibly due to a high average intake. CONCLUSIONS: This study reports a substantial association between in utero diet in a well-nourished population and later bone mass in their children. However, it does not allow identification of the dietary components of greatest importance, indicating that these results should be regarded as hypothesis-generating. Further longitudinal studies in other populations are required to confirm that dietary manipulation during pregnancy has a role to play in the early life prevention of osteoporosis.

Vitamin D levels in prepubertal children in Southern Tasmania: prevalence and determinants.

OBJECTIVE: To describe the prevalence and determinants of 25-hydroxy D3(25(OH)D) in children. DESIGN: Cross-sectional study. SETTING: Southern Tasmania between June and November 1997. SUBJECTS: Two hundred and one 8-y old male and female children taking part in a cohort study whose principal endpoints were blood pressure and high-density lipoprotein (HDL) cholesterol. RESULTS: The mean 25(OH)D level was 79 nmol/l (s.d. 29.5, median 73, range 12-222). Boys had higher levels than girls (82.1 vs 72.8 nmol/l, P=0.02). 25(OH)D was associated with sunlight exposure in winter school holidays (r=0.20, P=0.005) and winter weekends (r=0.16, P=0.02), the month after school holidays (87.5 vs 69.5 nmol, P<0.0001) and body mass index (r=-0.23, P=0.001). Dietary intake of vitamin D was low (mean 40 IU/day, range 5.2-384) and was not associated with 25(OH)D levels (r=0.01, P=0.91). Variation in skin melanin density was weakly associated with 25(OH)D (r=0.09, P=0.19). CONCLUSIONS: Sunlight is the major determinant of vitamin D stores in our population. Neither variation in skin type within Caucasians nor diet modified this association to any significant extent. Extrapolation of these findings to sunlight bone mass associations in a very similar population suggests that a minimum level of around 50 nmol/l in the population is required for optimal bone development in prepubertal children but this needs to be confirmed with further controlled trials of vitamin D supplementation and bone mass. SPONSORSHIP: Arthritis Foundation of Australia, Roche Pharmaceuticals.

Microalbuminuria is positively associated with usual dietary saturated fat intake and negatively associated with usual dietary protein intake in people with insulin-dependent diabetes mellitus.

Microalbuminuria has a cumulative incidence of > 30% in persons by 25 y duration of insulin-dependent diabetes mellitus (IDDM) and is a strong predictor of renal disease and mortality. Although improved glycemic control, maintenance of normal blood pressure, and use of angiotensin-converting enzyme inhibitors are important strategies to avoid developing microalbuminuria, dietary macronutrient intake may also play a role. A cross-sectional population-based study of Tasmanian adults with IDDM and no previous diagnosis of microalbuminuria was conducted by measuring usual dietary macronutrient intake with a food-frequency questionnaire and defining microalbuminuria as an average urinary albumin excretion rate between 20 and 200 micrograms albumin/min in at least two of three timed overnight urine collections. After sex, age, duration of diabetes, daily number of insulin injections, body mass index, glycated hemoglobin, serum high-density-lipoprotein cholesterol, frequency of exercise, and smoking status were adjusted for, the adjusted odds ratio for microalbuminuria for the highest quintile of energy-adjusted usual saturated fat intake compared with the lowest quintile was 4.9 (95% CI: 1.2, 20.0; P = 0.03). The adjusted odds ratio for microalbuminuria for the highest quintile of energy-adjusted usual protein intake compared with the lowest quintile was 0.10 (95% CI: 0.02, 0.56; P = 0.01). There was no significant association between microalbuminuria and energy-adjusted carbohydrate intake, energy-adjusted monounsaturated fat intake, or energy-adjusted polyunsaturated fat intake.

Parental history of diabetes in an insulin-treated diabetes registry.

To confirm observations of an excess maternal transmission of Type 2 (non-insulin dependent) diabetes mellitus in a setting which minimizes potential biases and confounders, we explored the patterns of maternal and paternal diabetes in a cohort (n = 1775) of subjects with insulin-treated diabetes mellitus (ITDM) in Tasmania, Australia. In order to identify individuals with Type 1 diabetes or insulin-treated Type 2 diabetes, cases were classified into groups based on their age at diagnosis and subsequent time to commencement of insulin. Individuals initially diagnosed younger than age 30 (predominantly Type 1 diabetes cases) reported a similar percentage of mothers and fathers with diabetes, but individuals diagnosed at age 30 or older (predominantly insulin-treated Type 2 diabetes) reported a maternal excess of diabetes. Having an elevated body mass index was associated with a higher frequency of maternal diabetes, but not of paternal diabetes. Because both childhood-onset Type 1 diabetes and adult-onset insulin-treated Type 2 diabetes cases were subject to the same potential study biases, these results offer support for an excess maternal role in Type 2 diabetes transmission.

Drowning fatalities of children in Tasmania: differences from national data.

All drownings of people under 15 years of age in Tasmania from 1981 to 1993 were identified from the Tasmanian coroner's case files. Age- and sex-specific mortality rates were calculated and found to be similar to Australian drowning mortality rates. An exception was the lower drowning rate for Tasmanian females aged 0 to 4 years. Only 9 per cent of drowning deaths were caused by immersion in a swimming pool, 32 per cent of deaths occurred in dams and ponds and 21 per cent occurred in a river. Most drownings (88 per cent) associated with dams, ponds, swimming pools and baths were in the 0-to-4-year age group. Compared with Australia as a whole, toddlers drowning in swimming pools is uncommon in Tasmania; however, there are relatively more drownings in dams and ponds. Strategies for the prevention of drowning in childhood in Tasmania should consider the hazards associated with rural living.

Comparative validity of a food frequency questionnaire for adults with IDDM.

OBJECTIVE: To investigate the characteristics of a food frequency questionnaire (FFQ) in measuring dietary intake in an adult insulin-dependent diabetes mellitus (IDDM) population. FFQs have been widely used in developed countries to assess usual dietary intake; however, information regarding the application of the method to individuals advised to follow a specific dietary regimen (such as people with IDDM) is scarce. RESEARCH DESIGN AND METHODS: The measurement of energy and macronutrients by an interviewer-administered FFQ was assessed in 84 adults, who were representative of adults with IDDM in Tasmania, Australia, by comparing it with 2 days of weighed dietary records. Mean daily energy and macronutrient intakes by each method were compared, and Pearson correlation coefficients were calculated for both unadjusted and energy-adjusted macronutrient intakes. RESULTS: The ratio of within-person to between-person variance in dietary estimates from weighed records was 0.53 for energy, 0.70 for fat, 2.55 for protein, 0.50 for carbohydrate, 0.78 for saturated fat, and 3.56 for dietary cholesterol. The correlation coefficient between the FFQ and a 2-day weighed dietary record for the same nutrients ranged from 0.38 for protein intake to 0.60 for saturated fat intake. The correlation coefficient between the FFQ and true usual dietary intake was estimated to be 0.60 for energy-adjusted fat intake, 0.36 for energy-adjusted protein intake, 0.72 for energy-adjusted carbohydrate intake, 0.55 for energy-adjusted saturated fat intake, and 0.77 for energy-adjusted cholesterol intake. CONCLUSIONS: People with IDDM had a low ratio of within-person to between-person variance in daily energy, fat, carbohydrate, saturate fat, and cholesterol intake. The performance of the FFQ in the IDDM population is consistent with similar questionnaires in nondiabetic populations; however, there was a significant decrease in the dietary energy estimate upon readministration of the questionnaire. Validation studies such as this are important to provide information to guide the design and analysis of investigations that use dietary questionnaires.

The 1984 Tasmanian insulin treated diabetes mellitus prevalence cohort: an eight and a half year mortality follow-up investigation.

Total mortality and underlying cause of death were examined in a population-based prevalence cohort (n = 1232) of Tasmanians with insulin-treated diabetes mellitus. Eight and a half years after the establishment of the registry, the cause of death based on death certificate information was determined for the overall cohort and for three classification groups of insulin-treated diabetes: Group A--childhood-onset IDDM cases; Group B--adult-onset IDDM cases; and Group C--adult-onset insulin-treated NIDDM cases. A total of 378 deaths occurred, providing an overall SMR of 2.2 (95% CI 2.0-2.4) compared to the Tasmanian population. Diabetic females experienced a higher SMR (2.6, 95% CI 2.3-3.0) than diabetic males (1.9, 95% CI 1.6-2.2). The all-cause SMRs for the diabetic classification groups were 4.6 (95% CI 3.4-6.1) in Group A, 1.8 (95% CI 1.5-2.1) in Group B, and 2.2 (95% CI 1.9-2.6) in Group C. After adjusting for age, gender and duration of diabetes, the mortality in Group C was significantly higher compared to Group B (odds ratio 1.6, 95% CI 1.2-2.3). This study indicates that people with childhood-onset IDDM experience 4.6 times the death rate compared to the Tasmanian population and that the excess mortality is most pronounced in females.

Effects of the heavy usage of kava on physical health: summary of a pilot survey in an aboriginal community.

Health status was assessed in 39 kava users and 34 non-users in a coastal Aboriginal community in Arnhem Land. Twenty (27%) respondents were very heavy (mean consumption, 440 g/week) users of kava; 15 (21%) respondents were heavy (310 g/week) users of kava and four (5%) respondents were occasional (100 g/week) users of kava. Kava users were more likely to complain of poor health and a "puffy" face, and were more likely to have a typical scaly rash, and slightly-increased patellar reflexes. Very heavy users of kava were 20% underweight and their levels of gamma-glutamyl transferase were increased greatly. Albumin, plasma protein, urea and bilirubin levels were decreased in kava users, and high-density lipoprotein cholesterol levels were increased. Kava users were more likely to show haematuria, and to have urine which was poorly acidified and of low specific gravity. The use of kava was also associated with an increased red-cell volume, with a decreased platelet volume and with a decreased lymphocyte count. Shortness of breath in kava users was associated with tall P waves on a resting electrocardiogram, which provided suggestive evidence of pulmonary hypertension. In common with other Aboriginal communities, there was evidence of decreased lung volumes, a high carriage rate of hepatitis B surface antigen, and of other morbidity that was unrelated to the use of kava. On the basis of these findings, there is a strong rationale for urgent social action to improve health in Aboriginal communities and, in particular, to reduce the consumption of kava and to improve the nutritional status of kava users.