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Developmental and generational trends in alcohol, cannabis and tobacco use--a ten year cohort analysis.

Six surveys of drug use (including alcohol) among Ontario (Canada) students (grades 7-13) were conducted between 1968-1979. Cohort analyses identified significant increases in the prevalence and incidence of alcohol and cannabis use for all cohorts with, however, some moderation of cannabis use in recent years within the oldest cohort. Recent tobacco use has shown a reduction in the earlier strong trends towards increased use. Developmental influences on drug use were stronger than generational influences. Implications for preventive intervention are discussed.

Adolescent↗

The Edinburgh City Hospital cohort: analysis of enrollment, progression and mortality by baseline covariates.

We describe baseline characteristics, enrollment, progression and mortality of the Edinburgh City Hospital HIV cohort. There were 431 men and 191 (31%) women; 439 (71%) infected via injection drug use (IDU); 92 (15%) via homosexual intercourse; 84 (13%) via heterosexual intercourse and 7 from blood products. Median annual rate of CD4 cell loss was 49 (90% range: 15-146); Both homosexual men and patients aged > 40 years at enrollment lost CD4 cells significantly more quickly. In multifactorial analysis controlled for baseline CD4 count and IgA, there was no gender effect, but young patients (< 25 years) progressed significantly more slowly to AIDS (RR 0.4, p = 0.00). Homosexual men progressed significantly more quickly than IDUs, with adjusted relative risks (RR) of 2.9 (p = 0.00), 2.5 (p = 0.01) and 1.5 (p = 0.1) for progression to CDC stage IV, AIDS and death, respectively. The three-year survival rate post-AIDS was 25% (SE 4.3) and there was no gender effect on survival. There was, however, an age effect whereby individuals diagnosed with AIDS in their 40s or later showed poorer survival (RR 1.9, p = 0.04). Zidovudine treatment after an AIDS diagnosis significantly lengthened post-AIDS survival (RR 0.5, p = 0.08).

Acquired Immunodeficiency Syndrome↗

Age-period-cohort analysis of motor vehicle mortality in Taiwan, 1974-1992.

The aim of this study was to examine the effects of age, calendar period of death and birth cohort in motor vehicle mortality in Taiwan over the period 1974-1992. A log-linear model modified from the method of Osmond and Gardner (Stat. Med. 1: 245-259; 1982) was used. Age turned out to be a significant predictor of motor vehicle mortality. The most risky group (over 70 years) had 27.1 and 16.3 times the mortality of the least risky group (5-9 years, 10-14 years) for males and females respectively. The period effect showed a continuously increasing mortality trend since 1974 in females. The pattern in males is similar except that it has slightly leveled off in recent years. The birth cohorts at the highest risk of motor vehicle death were those born between 1979 and 1983 for both sexes. However, males born between 1929 and 1933 also had a high mortality. This analysis provided a better understanding of the trend of mortality from motor vehicle crashes.

Accidents, Traffic↗

Costs and outcomes of tuberculosis control in the Russian Federation: retrospective cohort analysis.

We analysed costs and outcomes of tuberculosis care for patients in a traditional Russian tuberculosis control system, using 3-year retrospective cohort data. Of 1749 cases at 3 years of follow-up, 65% were cured, 11.3% (198/1749) still had 'active' or 'chronic' disease, 10.3% had transferred out of the local civilian health care system and 12.7% had died. The mean cost of managing one case over 3 years was 886 US dollars: 1,078 US dollars for bacteriologically confirmed (BK+) cases and 718 US dollars for bacteriologically unconfirmed (BK-) cases. Approximately 60% of treatment costs were incurred in the first 12 months and 40% incurred in the remaining 2 years. Around 60% of the total cost was accounted for by hospital inpatient care. The cost, treatment and outcome of BK+ and BK- cases differed substantially. The cost of treating BK+ cases was 50% higher than treating BK- cases due to higher hospitalization rates and the additional cost of managing BK+ cases that become 'chronic'. While BK+ cases accounted for 55% of total health expenditure on tuberculosis, the share of BK- cases was 45% of the total - due to hospitalization and lengthy periods of follow up. The costs of treating tuberculosis in the Russian tuberculosis control system are very high compared with other high-burden countries due to hospitalization policies and lengthy case management periods. Much of this expenditure can be avoided if the WHO-recommended DOTS strategy is implemented. In particular, the proportion of expenditure for BK- cases is surprisingly high and can be avoided as most of these patients do not need hospitalizing or lengthy periods of follow-up.

Adult↗

Elementary methods of cohort analysis.

The Mantel-Haenszel procedure offers a simple and efficient means of estimating a common rate ratio from incidence density data in cohort studies. A new formula is provided for the variance of its logarithm, comparisons are made with the method of maximum likelihood, and associated tests for heterogeneity and trend in the component rate ratios are described.

Adult↗

Antioxidant enzymes, inflammatory indices and lifestyle factors in older men: a cohort analysis.

We examined the relationship between blood antioxidant enzyme activities, indices of inflammatory status and a number of lifestyle factors in the Caerphilly prospective cohort study of ischaemic heart disease. The study began in 1979 and is based on a representative male population sample. Initially 2512 men were seen in phase I, and followed-up every 5 years in phases II and III; they have recently been seen in phase IV. Data on social class, smoking habit, alcohol consumption were obtained by questionnaire, and body mass index was measured. Antioxidant enzyme activities and indices of inflammatory status were estimated by standard techniques. Significant associations were observed for: age with alpha-1-antichymotrypsin (p < 0.0001) and with caeruloplasmin, both protein and oxidase (p < 0.0001); smoking habit with alpha-1-antichymotrypsin (p < 0.0001), with caeruloplasmin, both protein and oxidase (p < 0.0001) and with glutathione peroxidose (GPX) (p < 0.0001); social class with alpha-1-antichymotrypsin (p < 0.0001), with caeruloplasmin both protein (p < 0.001) and oxidase (p < 0.01) and with GPX (p < 0.0001); body mass index with alpha-1-antichymotrypsin (p < 0.0001) and with caeruloplasmin protein (p < 0.001). There was no significant association between alcohol consumption and any of the blood enzymes measured. Factor analysis produced a three-factor model (explaining 65.9% of the variation in the data set) which appeared to indicate close inter-relationships among antioxidants.

Acute-Phase Proteins↗

Age-period-cohort analysis of dentist use in Spain from 1987 to 1997. An analysis based on the Spanish National Health Interview Surveys.

The aim was to determine whether the effects of age, period (from 1987 to 1997), or cohort (birth-cohort) are the most plausible explanations for the variation in dentist utilisation over time in Spain. On the basis of three sequential Spanish National Health Surveys, the trend in the percentage of people visiting the dentist within the previous 3 months was analysed by means of a standard cohort table and by the CLAYTON & SCHIFFLERS method. The percent of people visiting the dentist grew from 13.6% in 1987, to 17.2% in 1997. Visual examination of the cohort table, together with the fit of the age-cohort model, indicates that cohort succession may be the best explanation for the increase. The younger the cohort, the higher the dental visit rate; this relationship was strongest for people born after 1977. The model also indicates that the rates of dental visiting tend to increase up to middle age, and then tend to decrease with age.

Adolescent↗

Cohort analysis of fruit and vegetable consumption and lung cancer mortality in European men.

Our aim was to examine the relationship between fruit and vegetable consumption and lung cancer mortality in a cohort of European males. Around 1970, dietary intake of Finnish, Italian and Dutch middle-aged men was assessed using a cross-check dietary history. Complete baseline information was available for 3,108 men, of whom 1,578 were baseline smokers. We used Cox proportional hazard analyses to calculate risk estimates for the consumption in country-specific tertiles on lung cancer in smokers. During 25 years of follow-up, 149 lung cancer deaths occurred in the smokers. Fruit consumption was inversely associated with lung cancer mortality among smokers; compared with the lowest, adjusted RRs for the intermediate and highest tertiles were 0.56 (0.37-0.84) and 0.69 (0.46-1.02), p-trend 0.05. Only in the Dutch cohort was this association statistically significant [adjusted relative risks (RRs) 1.00, 0.33 (0.16-0.70) and 0.35 (0.16-0.74), p-trend 0.004]. In Finland lung cancer risk was lower with higher fruit intake but not significantly, whereas in Italy no association was observed. Stratifying on cigarette smoking intensity (non, light and heavy) revealed an inverse association in the heavy smokers only [adjusted RRs (95% confidence intervals [CI]) 1; 0.47 (0.26-0.84); 0.40 (0.20-0.78)). Vegetable consumption was not related to lung cancer risk in smokers. However, analyses stratified on cigarette smoking intensity gave some indication for a lower lung cancer risk with higher intake. In conclusion, in this prospective analysis among European smoking men, fruit intake was inversely related to lung cancer mortality. This association was confined to heavy cigarette smokers.

Adult↗