Spreading of chronic pain between body regions: prospective cohort study among health care workers.

OBJECTIVE: To estimate the prognostic value of pain in one body region on the risk for developing chronic pain in other body regions. METHODS: Prospective cohort study among 5052 Danish female health care workers responding to a baseline and follow-up questionnaire in 2005 and 2006, respectively. Using adjusted logistic regression analysis, the risk for developing chronic pain (>30 days last year) at follow-up in the low back (among those without low back pain during the last year at baseline) when experiencing sub-chronic (1-30 days last year) or chronic pain in other body regions (i.e., the neck/shoulders and/or the knees at baseline) was modelled. Similar risks were modelled for developing chronic pain in the neck/shoulders and knees. RESULTS: Chronic pain in the neck/shoulders (OR 3.14; 95% CI 1.74-5.70) or knees (OR 2.57; 95% CI 1.28-5.16) at baseline increased the risk for developing chronic pain in the low back at follow-up. Likewise, chronic pain in the neck/shoulders (OR 2.39; 95% CI 1.36-4.17) or low back (OR 1.82 95%; CI 1.07-3.09) at baseline increased the risk for developing chronic pain in the knees at follow-up. The risk for developing chronic neck/shoulder pain was not significantly increased when having pain in the low back or knees at baseline. CONCLUSION: Among health care workers, chronic musculoskeletal pain in one body region increases the risk for developing chronic pain in other pain-free body regions. Prevention of musculoskeletal disorders among health care workers should focus holistically on the musculoskeletal system.

High intake of energy, sucrose, and polyunsaturated fatty acids is associated with increased risk of preeclampsia.

OBJECTIVE: Preeclampsia is associated with high body mass index, insulin resistance, and hypertriglyceridemia. Our objective was to investigate prospectively whether diet in the first half of pregnancy is associated with the risk for preeclampsia. STUDY DESIGN: This prospective, population-based, cohort study of pregnant women investigated dietary intake early in the second trimester with a quantitative food frequency questionnaire. RESULTS: The questionnaire was completed by 3133 women (83%). Preeclampsia developed in 85 women. Adjusted odds ratio (95% CI) for preeclampsia was 3.7 (1.5-8.9) for energy intake of >3350 kcal/d compared with < or =2000 kcal/d. Adjusted odds ratio (95% CI) for preeclampsia was 3.6 (1.3-9.8) for sucrose intake (percent of total energy) of >25% compared with < or =8.5% and 2.6 (1.3-5.4) for polyunsaturated fatty acids intake (percent of total energy) of >7.5% compared with < or =5.2%. Other energy-providing nutrients were not associated with the risk for preeclampsia. CONCLUSION: The current study suggests that high intakes of energy, sucrose, and polyunsaturated fatty acids independently increase the risk for preeclampsia.

Incidence of nursing sickness and biochemical observations in lactating mink with and without dietary salt supplementation.

The impact of dietary sodium on the incidence of nursing sickness in mink dams and on the average litter biomass of 28 and 42 day old kits was studied. One group (n = 115 including 12 barren females) was given a standard feed mixture with a natural content of 0.53 g NaCl/MJ and another group (n = 115 including 8 barren females) was given the same feed mixture supplemented with NaCl to a final content of 1.00 g/MJ. The average dam weight at weaning was significantly lower (P < 0.001) and the incidence of nursing sickness during the last part of the lactation period 3 times higher in the nonsupplemented group. The average litter biomass at weaning did not differ between the 2 experimental groups. A number of biochemical markers of preclinical nursing sickness, e.g. plasma aldosterone and osmolality, Na+ and Cl concentrations in plasma and urine, were studied during the last part of the lactation period and at weaning in 20 dams of the nonsupplemented group, in 10 dams of the salt supplemented group and, for comparison, in 5 + 5 barren females on the day corresponding to day 34 after parturition in nursing mink. The nonsupplemented group had significantly lower concentrations of sodium and chloride in plasma and urine and a significantly higher concentration of plasma aldosterone as compared to the salt supplemented group. Distinct signs of relative salt deficiency and preclinical nursing sickness thus characterized the nonsupplemented group throughout this period, while more blurred hints of electrolyte imbalances were noticed in the sodium chloride supplemented group at weaning. A beneficial effect of salt supplementation on the incidence of nursing sickness was shown; however, it remains unclear whether salt deficiency can cause nursing sickness or whether salt acts as an appetite stimulant preventing inanition and the development of the disorder.

Reduced concentrations of potassium, magnesium, and sodium-potassium pumps in human skeletal muscle during treatment with diuretics.

Animal studies have shown that potassium depletion induced by diuretics or potassium deficient fodder leads to a selective decrease in the concentrations of potassium and in the concentration of sodium-potassium pumps in skeletal muscle. In 25 patients who had received diuretics for 2-14 years the mean concentrations of potassium, magnesium, and sodium-potassium pumps were measured in skeletal muscle biopsy specimens and were significantly lower than in those from a group of age matched controls. The reductions in all three variables were significant in those patients receiving diuretics for arterial hypertension as well as in those being treated for congestive heart failure. In 14 patients the mean muscle potassium concentration was below the control range, but only one of those was hypokalaemic (3.4 mmol/l), and 13 were receiving potassium supplements. In 15 patients the mean muscle magnesium concentration was below normal, and the mean muscle potassium and magnesium concentrations showed a linear correlation. In 12 patients in whom the mean muscle potassium concentration was below 80 mumol/g wet weight there was a linear correlation between the cellular potassium:sodium ratio and the concentration of 3H-ouabain binding sites indicating that potassium deficiency also leads to a down regulation of sodium-potassium pumps in human skeletal muscle. In spite of potassium supplements long term treatment with diuretics may lead to potassium and magnesium deficiencies, which are not detectable using the standard methods of serum analysis. The changes in concentrations of electrolytes and sodium-potassium pumps associated with treatment with diuretics may impair muscle function and potassium homoeostasis and interfere with the distribution of digitalis glycosides.

Inadequate supplies of potassium and magnesium in relief food--implications and countermeasures.

Analyses of relief food used in Ethiopia showed that, because of food refinement, 6 out of 10 samples of cereals contained too little potassium and magnesium to cover daily needs. Malnutrition is often associated with gastrointestinal infections, which lead to further deficiency of these electrolytes. Potassium and magnesium are required for protein synthesis, growth, and tissue repair. Since protein supplies are often marginal, relief food should contain sufficient potassium and magnesium to allow optimum utilisation of dietary nitrogen sources. This may be achieved by using coarse qualities of cereals, by supplementing cereals with legumes, and by avoiding cooking procedures that extract these salts from the cereals.

The effect of hyperosmolarity and insulin on resting tension and calcium fluxes in rat soleus muscle.

1. The effect of hyperosmolarity on resting tension and on the fluxes of Na and Ca has been characterized in isolated soleus muscles of the rat. 2. When the osmolarity of the incubation medium was increased by the addition of non-permeant solutes (100-400 m-osmole), the tension showed a rapid dos-dependent rise which could be maintained for up to 60 min. 3. Tension development was unaffected by tubocurarine (2 X 10(-5) M), considerably diminished by the omission of Na or Ca from the incubation medium, and inhibited by tetracaine (10(-4) M). 4. The addition of mannitol or sucrose (200 mM) induced a prompt stimulation of the influx of 22Na and 45Ca. Both in the absence and the presence of extracellular Ca hyperosmolarity stimulated the washout of 45Ca from preloaded muscles. Tetracaine (5 X 10(-4 M) suppressed the effects of hyperosmolarity on both the influx and the efflux of 45Ca, but only gave a modest reduction in the stimulation of 22Na influx. 5. Insulin (5-100 mu./ml.) induced a considerable further rise in the resting tension of muscles exposed to mannitol or sucrose (200 mM). This effect was seen in a glucose-free medium and could be abolished by the addition of insulin antibody. 6. It is concluded that hyperosmolarity leads to a rise in the concentration of free Ca2+ ions in the sarcoplasm, partly due to a mobilization of Ca from intracellular pools, but to a considerable extent supplemented from extracelluar sources. Under these conditions, insulin further augments the Ca2+ ion level in the cytoplasm.