ABSTRACT
A study sample of 7,010 episodes of invasive Streptococcus pneumoniae disease was obtained by combining 13 existing datasets. Disease episodes due to each of 12 pneumococcal serogroups (1, 3-9, 14, 18, 19, and 23) were then compared with episodes in a constant internal control group to describe serogroup-specific variations in disease frequency by age, sex, and geographic origin. The results are presented as odds ratios (with 95% confidence intervals) derived by logistic regression, with adjustment for the major confounders, including dataset of origin. Variation in the male:female ratios between serogroups is small, suggesting that capsular characteristics are an unlikely explanation for the male preference of S. pneumoniae. Serogroups associated with higher nasopharyngeal prevalence (e.g., 19 and 24) are relatively more common in Europe and North American, while the invasive serotypes 1 and 5 are much more common in South America. The custom of reporting serogroup frequencies in two age groups, children and adults, conceals much of the variation in the age distributions across the whole span of life. The reduction of risk associated with serogroups 6, 14, 18, 19, and 23 beyond childhood follows different gradients, being most abrupt in serogroups 14 and most gradual in serogroup 18. The relative risk of disease with serotype 1 declines steadily throughout life, while with serotypes 3 and 8 it increases over middle age. Serogroups 7 and 23 are found unusually frequently in the third decade of life. Because of the wide differences in the epidemiology of individual serogroups of S. pneumoniae, it is questionable whether pneumococcal infection should continue to be classified as a single disease entity.
Subject(s)
Pneumococcal Infections/epidemiology , Serotyping/classification , Streptococcus pneumoniae/classification , Adolescent , Adult , Age Factors , Aged , Brazil/epidemiology , Canada/epidemiology , Child , Child, Preschool , Female , Humans , Israel/epidemiology , Male , Middle Aged , Odds Ratio , Seroepidemiologic Studies , Sex Factors , Spain/epidemiology , United Kingdom/epidemiology , United States/epidemiology , Uruguay/epidemiologyABSTRACT
A quantification method for measuring whole saliva is described. This whole saliva test (WST) consists of a Whatman paper strip, is easily carried out, innocuous, low-cost and single use. Due to its characteristics, it could be considered as the oral equivalent of Schirmer's tear test. A sample of 159 healthy subjects (81 males and 78 females; mean age 31.62 years) participated in this comparative study of this new procedure and two other tests, the draining and the swab test. Correlation was statistically positive among the three types of tests.
Subject(s)
Saliva/metabolism , Salivation/physiology , Specimen Handling/methods , Adolescent , Adult , Aged , Child , Child, Preschool , Evaluation Studies as Topic , Female , Humans , Linear Models , Male , Middle Aged , Secretory Rate , Specimen Handling/instrumentationABSTRACT
OBJECTIVE: Evaluation of the resting whole saliva secretion rate in relation to age. MATERIAL AND METHODS: A sample of 1493 healthy subjects between 5 and 88 years of age (691 men and 802 women). A new objective procedure for whole saliva quantification, the Whole Saliva Test (WST), was used. RESULTS: Resting whole saliva was found to decrease with age (Pearson's coefficient: r = 0.273; P = 0.0001). CONCLUSION: Resting whole saliva decreases with age.