Changes in the incidence of amyotrophic lateral sclerosis in Wakayama, Japan
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In the 1960s, the incidence of amyotrophic lateral sclerosis (ALS) in the Kozagawa and Koza areas in Wakayama prefecture was much higher than that in other areas of the world. However, between 1980 and 1993, a gradual decrease in the incidence of the disease in these areas was reported. To ascertain whether the decreased incidence has persisted, we conducted a retrospective epidemiological study, and determined the average annual incidence of ALS in Wakayama prefecture from 1998 to 2002. The number of ALS cases encountered during the period was 134 (male 79, female 55). The crude average annual incidence in Wakayama prefecture in total was 2.50 (male 3.08, female 1.99) per 100,000. In the Kozagawa and Koza areas in Wakayama prefecture, where the senility rate rapidly increased in recent years, the average annual incidence of ALS in the present research was 10.56 (male 14.14, female 7.66). When the crude rate was standardized for both age and sex to the Japanese population in 1990, the expected value was 5.24 (male 7.34, female 3.18), which was lower than that of our previous survey. The prevalence in Wakayama prefecture at 31 December 2002 was 11.31 (male 14.40, female 8.53). In Kozagawa and Koza areas, the crude prevalence was 52.81 (male 70.70, female 38.28). These results indicated that the incidence of ALS in Wakayama prefecture, especially for females, steadily decreased compared to that in previous reports. However, a high incidence of ALS persisted among males in Wakayama prefecture, especially in the Kozagawa and Koza areas. Some environmental factors and gender specificity may be related to the decreased incidence of ALS in focus areas.The effect of population structure on five-year age-specific incidence rates was investigated using the one-year population data from life tables and a theoretical age incidence curve of the form: I = btk - where I is the incidence at age t, and b and k are constants. The five-year incidence rates differed systematically from the one-year rates of the central year of the five-year period. This difference depended on the change with age of both the population size and the incidence rate. Thus at ages 20-24 the five-year rate overestimates the mid-period one-year rate by about 4%, but the overestimate progressively decreases to become an underestimate of 0.5% at ages 75-79. In consequence the one-year and five-year rates produce fitted age incidence curves with different slopes; the value of k in the incidence equation is about 0.7% greater for the one-year rates. The population structures of developed and underdeveloped countries are markedly different and these were found to affect the five-year incidence rates, but never by more than 0.5%. The effect of the irregularities in one-year age structure of real populations on the observed five-year rates is also small, of the order of 0.5%. However, when incidence rates are calculated by recording tumours over several calendar years, these irregularities can create difficulties for the estimation of the appropriate denominator population. The use of the census population, even that of the central year of the observation period, can be in error by over 2%. A good method is to calculate the mean annual population of the observation period, estimating the intercensal year populations by interpolation between flanking censuses.
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In recent years, the proportion of male babies has become larger and larger. According the Bulletin of Major Data from 1990 Census (Number 6) published by the State Statistical Bureau in May 20, 1991, on an average, the rate of male is 51.45%, and the rate of female is 48.55%; however, for 0-13 age group, the rate of male is 51.99%, and the rate of female is 48.01%. It means that, within 14 years before July 1, 1990, the sex ratio of newly-born babies had raised by 2.32%. With the further analysis, we can also see that the sex ratio in any year of the 14 years is higher than that of the total population. Moreover, the younger, the larger the proportion of male is and the smaller the proportion of female is. The unusual sex ratio will have a direct effect on marriage. In about 20 years, each year there will be 1.2 million males who will not be able to find a girl to marry. Therefore, it is imperative that macroscopic regulation and control of sex ratio be taken as an important part of family planning work.
Girl
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The study on the sex ratio of overall population and of children in 0-6 age group for different districts in Punjab concentrates on the following: i. Is there any likely relationship between overall male population and overall female population with respect to rural and urban areas (in particular, are there any significant patterns?). ii. Is there any significant difference between overall male 0-6 population, overall female 0-6 population with respect to rural and urban areas. iii. Is there any significant difference between the proportion of female population and female 0-6 population with respect to all districts (in particular, are there any significant patterns?). iv. Is there any significant difference among the districts with respect to overall male and overall female population (in particular, are there any significant patterns?). v. Is there any significant difference among the districts with respect to overall male 0-6 and overall female 0-6 population (in particular, are there any significant patterns?). vi. Also a scientific arrangement of the district wise path is evaluated by lexisearch method for the first time for demographic data.
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Background: Malta, the smallest island state in Europe, with an approximate population of 400,000, has one of the lowest reported incidence rates for tuberculosis (TB) in its native-born population. 1 Longterm trends for TB among this population were investigated. Methods: A period of 35 years (1979-2013) for the Malta-born population was investigated using single-age population numbers for each year, retrospective, and partly prospective analysis of notified TB cases. Mean five-yearly populations were then used to calculate 5yearly incidence rates for birth-cohorts, age-groups, major site and gender. Annual reported TB incidence rates were also calculated. Results: In the Malta-born population, over the 35year period, reported yearly TB incidence shows a downward, albeit decelerating trend. Consecutive follow-up of 5-year age-cohorts and 5-year age-groups confirms that incidence has fallen, with the highest rates being observed in progressively older age-groups. A falling trend in TB incidence according major site and gender was also observed. Conclusion: TB is being successfully controlled among the Malta-born population, and confirmed to be slowly approaching the elimination phase. 2
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"In this paper, the recent changes in sex differentials in India's mortality are studied first to ascertain the relative improvements and secondly to study the impact of these changes on [the] sex ratio of the population. The analysis...indicates that the reduction in mortality rates during 1971-1991 was higher for females, particularly...during 1981-91. The narrowing down of the gap between male and female mortality rates had started in the late 1970s and all the indicators considered here suggest that, at present, there is an excess of male mortality in India. The mortality change was favourable for improvement in sex ratio; the analysis shows that the changes in mortality differentials by sex alone would have led to an increase in sex ratio by more than 10 points during the last decade. Further analysis suggests that the sex ratio at birth in India changed considerably during the last decade and [that] most of the reduction in sex ratio [that] occurred during 1981-91 can be attributed to these changes."
Standardized mortality ratio
Excess mortality
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There is growing imbalance in the male-female ratio. Sex-ratio is a three tier phenomenon. First, it means the number of females per 1000 males in respect to the total population. Secondly, sex-ratio at birth indicates the number of female children born per 1000 males children. Thirdly sex-ratio in the lowest age group among children from birth to six years. As per 2001 census, the overall sex-ratio of India is 933 females per 1000 males which is less than the overall international sex-ratio of 986 females per 1000 males. Hence it was thought relevant to study awareness of rural couples on these issues. The study was conducted by selecting two villages Palpur and Ravanika from two blocks of district Allahabad from Uttar Pradesh by random selection. From each village a sample of 50 couples under the age of 45 years were randomly selected to make a total sample size of 100 couples. Awareness about sex-ratio, quite a large number of males (64%) and females (74%) had no knowledge about it. Females foeticide was cited by respondents (41% male and 36% females) as the main reasons for the imbalanced sex-ratio. Eighty one per cent males and 65 per cent females felt that the major problem due to imbalanced sex-ratio would be non-availability of brides.
Sex selection
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Multiple sclerosis (MS) is thought to be rare among North American aboriginals, although few population-based frequency studies have been conducted. Data from government health databases were used to describe the incidence of MS among First Nations aboriginal people in the province of Alberta compared to the general population from 1994 to 2002. The general population rates were consistently higher than First Nations rates, but were essentially stable across this time span for both groups. For First Nations the MS incidence was 7.6 per 100,000 and 20.6 per 100,000 for the general population in 2002. During 2000–2002 for First Nations the incidence was 12.7 for females and 7.6 for males, with a female-to-male ratio of 1.7:1. During the same period the general population incidence was 32.2 for females and 12.7 for males, with a female-to-male ratio of 2.5:1. The peak incidence for both First Nations and the general population of Alberta was in the age group 30–39 years in 2002. The high incidence rates are consistent with high prevalence rates reported for both groups in 2002: 99.9 per 100,000 for First Nations and 335.0 per 100,000 for the general population. While the MS incidence in First Nations people is lower than in the general population of Alberta, it is not rare by worldwide standards.
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The incidence and prevalence of motor neuron disease (MND) in the Province of Turin, North-West Italy, were investigated for the period 1971-1980. The crude incidence rate of MND was 0.67/100,000/year. The annual incidence rate, age and sex adjusted to the Italian population in 1971 was 0.69 cases per 100,000 inhabitants, 0.94 for men and 0.45 for women, with a male to female incidence ratio of 2.09:1. The prevalence of MND was 2.62/100,000, 3.57 for males and 1.71 for females. The mean age at the time of diagnosis was 55.6 years. Annual incidence rates increased with advancing age. Amyotrophic lateral sclerosis was found to be 4 times more frequent than progressive muscular atrophy (0.53/100,000/year v. 0.14/100,000/year). The distribution of MND was uneven in the Province suggesting a proportional relationship to the distribution of population density. Possible explanations of this finding are discussed.
Progressive muscular atrophy
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