Annual Percentage Change In Rates Research Articles

Age group-specific changes in keratinocyte cancer treatment rates in Australia, 2012-2021: a retrospective cohort study based on MBS claims data.

To examine recent changes in the numbers of Medicare-subsidised keratinocyte cancer excisions, particularly for younger people exposed to primary prevention campaigns since the early 1980s. Retrospective cohort study; analysis of administrative data. Analysis of Medicare Benefits Schedule (MBS) claims data for procedures related to the diagnosis and treatment of keratinocyte cancer in Australia, 2012-2021. Age-standardised rates for MBS-subsidised claims for first surgical squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) excisions, Mohs surgery, surgical excisions of benign lesions, skin biopsies, and cryotherapy or serial curettage of premalignant and malignant lesions, overall, and by sex, state/territory, and age group; average annual percentage change in rate for time intervals determined by joinpoint regression. In men, the age-standardised rate of BCC/SCC excisions increased by 1.9% (95% confidence interval [CI], 1.4-2.4%) per year during 2012-2019 (from 2931 to 3371 per 100 000 men) and then declined by 3.8% (95% CI, 0.5-7.0%) per year during 2019-2021 (to 3152 per 100 000). In women, the age-standardised rate increased by 2.2% (95% CI, 1.7-2.8%) per year during 2012-2019 (from 1798 to 2093 per 100 000 women); the decline to 1967 excisions per 100 000 women in 2021 was not statistically significant. BCC/SCC excision rates declined for men under 55 years of age (by 1.0-3.4% per year) and women under 45 years of age (by 1.7-2.3% per year). Age-standardised biopsy rates increased during 2012-2021 in all age groups (by 2.8-6.9% per year). Rates of MBS-subsidised treatment for keratinocyte cancers increased during 2012-2019, but BCC/SCC treatment rates declined among younger Australians, who have probably been exposed to less sunlight than earlier generations because of public health interventions and population-wide lifestyle changes related to technology use.

Recent trends of invasive mechanical ventilation in older adults: a nationwide population-based study.

Critical care demand for older people is increasing. However, there is scarce population-based information about the use of life-support measures such as invasive mechanical ventilation (IMV) in this population segment. To examine the characteristics and recent trends of IMV for older adults. Retrospective cohort study on IMV in adults ≥65years using the 2004-15 Spanish national hospital discharge database. Primary outcomes were incidence, inhospital mortality and resource utilization. Trends were assessed for average annual percentage change in rates using joinpoint regression models. 233,038 cases were identified representing 1.27% of all-cause hospitalizations and a crude incidence of 248 cases/100,000 older adult population. Mean age was 75years, 62% were men and 70% had comorbidities. Inhospital mortality was 48%. Across all ages, about 80% of survivors were discharged home. Incidence rates of IMV remained roughly unchanged over time with an average annual change of -0.2% (95% confidence interval (CI): -0.9, 0.6). Inhospital mortality decreased an annual average of -0.7% (95% CI: -0.5, -1.0), a trend detected across age groups and most clinical strata. Further, there was a 3.4% (95% CI: 3.0, 3.8) annual increase in the proportion of adults aged ≥80years, an age group that showed higher mortality risk, lower frequency of prolonged IMV, shorter hospital stays and lower costs. Overall rates of IMV remained roughly stable among older adults, while inhospital mortality showed a decreasing trend. There was a notable increase in adults aged ≥80years, a group with high mortality and lower associated hospital resource use.

Primary liver cancer in the UK: Incidence, incidence-based mortality, and survival by subtype, sex, and nation

Background & AimsThe incidence of primary liver cancer (PLC) is increasing in Western Europe. To understand trends over time and the current burden in the UK, a detailed analysis of the epidemiology of PLC and its subtypes was conducted.MethodsData on PLCs diagnosed during 1997–2017 were obtained from population-based, nationwide registries in the UK. European age-standardised incidence (ASR) and incidence-based mortality rates (ASMR) per 100,000 person-years were calculated overall and by sex and UK-nation. Annual percentage change in rates was estimated using Joinpoint regression. One-, 2-, and 5-year age-standardised net survival was estimated.ResultsA total of 82,024 PLCs were diagnosed. Both hepatocellular carcinoma (HCC) incidence and mortality rates trebled (ASR 1.8–5.5 per 100,000, ASMR 1.3–4.0). The rate of increase appeared to plateau around 2014/2015. Scottish men consistently had the highest HCC incidence rates. PLC survival increased, driven by a substantial increase in the proportion that are HCC (as prognosis is better than other PLCs) and in HCC survival (change in 1-year survival 24–47%). Intrahepatic cholangiocarcinoma was the most common PLC in women and 1-year survival improved from 22.6% to 30.5%.ConclusionsPLC incidence has been increasing rapidly but, as most risk factors are modifiable, it is largely a preventable cancer. This rate of increase has slowed in recent years, possibly attributable to effective treatment for hepatitis C. As other risk factors such as obesity and diabetes remain prevalent in the UK, it is unlikely the considerable burden of this disease will abate. While improvements in survival have been made, over half of patients are not alive after 1 year, therefore further progress in prevention, early detection, and treatment innovation are needed.Lay summaryMany more people are getting liver cancer, particularly the subtype hepatocellular carcinoma, than 20 years ago. Men in Scotland are most likely to get liver cancer and to die from it. Survival after liver cancer diagnosis is getting longer but still less than half are alive after 1 year.

Decade of variable progress: trends in fatal injury in workers in New Zealand from a national observational study

IntroductionAnalyses of secular trends in work-related fatal injury in New Zealand have previously only considered the total working population, potentially hiding trends for important subgroups of workers. This paper examines...

Space-time clustering and temporal trends of hospitalizations due to pulmonary tuberculosis: potential strategy for assessing health care policies.

Tuberculosis (TB) causes pressure on healthcare resources, especially in terms of hospital admissions, despite being considered an ambulatory care-sensitive condition for which timely and effective care in ambulatory setting could prevent the need for hospitalization. Our objectives were to describe the spatial and temporal variation in pulmonary tuberculosis (PTB) hospitalizations, identify critical geographic areas at municipality level and characterize clusters of PTB hospitalizations to help the development of tailored disease management strategies that could improve TB control. Ecologic study using sociodemographic, geographical and clinical information of PTB hospitalization cases from continental Portuguese public hospitals, between 2002 and 2016. Descriptive statistics, spatiotemporal cluster analysis and temporal trends were conducted. The space-time analysis identified five clusters of higher rates of PTB hospitalizations (2002-16), including the two major cities in the country (Lisboa and Porto). Globally, we observed a -7.2% mean annual percentage change in rate with only one of the identified clusters (out of six) with a positive trend (+4.34%). In the more recent period (2011-16) was obtained a mean annual percentage change in rate of -8.12% with only one cluster identified with an increase trend (+9.53%). Our results show that space-time clustering and temporal trends analysis can be an invaluable resource to monitor the dynamic of the disease and contribute to the design of more effective, focused interventions. Interventions such as enhancing the detection of active and latent infection, improving monitoring and evaluation of treatment outcomes or adjusting the network of healthcare providers should be tailored to the specific needs of the critical areas identified.

Evaluation of Sex-Specific Incidence of Melanoma

Men and women develop melanoma at different rates on different body sites, with variation across countries, but explanations for these disparities remain elusive. To test whether observed differences in melanoma incidence between men and women vary by population, age, or anatomic site. Cross-sectional analysis of sex- and site-specific temporal trends in melanoma incidence over 3 decades was conducted for men and women diagnosed with invasive melanoma in the US (limited to white race), Canada, Australia, New Zealand, the UK, Sweden, Norway, and Denmark. Using cancer registry data, male to female incidence rate ratios (IRRs) were calculated overall and by anatomic site, and Joinpoint regression models were used to estimate the annual percentage rate changes in sex- and site-specific incidence in each population. Incidence rates were standardized to the US 2000 population. Data on the incidence between January 1, 1982, and December 31, 2015, were obtained; analysis was conducted from March 1 to October 15, 2019. Male to female IRRs and annual percentage change in rates. Total melanoma incidence was higher in men than women in US individuals (limited to white race), Canada, Australia, and New Zealand, but not in Denmark, the UK, Norway, and Sweden. In all populations, men had higher rates of melanoma of the head and neck and trunk than women (male to female IRR >1), but lower melanoma rates on the lower limbs (ie, male to female IRR approximately 0.5). The male to female IRR increased log linearly with age, with excess melanomas in women younger than 45 years in all populations (eg, IRR for 20-24 y age group, 0.3 in Denmark and 0.7 in Australia), and excess melanomas in men older than 69 years (eg, IRR for 70-74 y age group, 1.1 in Denmark and 2.1 in the US white population). The age at which the melanoma incidence in men exceeded the melanoma incidence in women differed by population, being achieved the earliest in Australia (45-49 years) and latest in Denmark (65-69 years). In predominantly fair-skinned populations, melanoma incidence appears to differ systematically and consistently between men and women by age and anatomic site.

Analysis of cerebrovascular disease mortality trends in Andalusia (1980–2014)

IntroductionIn recent decades, mortality rates for cerebrovascular diseases (CVD) have decreased significantly in many countries. This study analyses recent tendencies in CVD mortality rates in Andalusia (1980-2014) to identify any changes in previously observed sex and age trends. Patients and methodsCVD mortality and population data were obtained from Spain's National Statistics Institute database. We calculated age-specific and age-standardised mortality rates using the direct method (European standard population). Joinpoint regression analysis was used to estimate the annual percentage change in rates and identify significant changes in mortality trends. We also estimated rate ratios between Andalusia and Spain. ResultsStandardised rates for both males and females showed 3 periods in joinpoint regression analysis: an initial period of significant decline (1980-1997), a period of rate stabilisation (1997-2003), and another period of significant decline (2003-2014). ConclusionsBetween 1997 and 2003, age-standardised rates stabilised in Andalusia but continued to decrease in Spain as a whole. This increased in the gap between CVD mortality rates in Andalusia and Spain for both sexes and most age groups.

Trends in Alcohol‐Related Emergency Department Visits in the United States: Results from the Nationwide Emergency Department Sample, 2006 to 2014

Acute alcohol consumption and chronic alcohol consumption increase the burden placed on emergency departments (EDs) by contributing to injury and disease. Whether the prevalence of alcohol-related ED visits in the United States has changed in recent years is unknown. The purpose of this study was to examine trends in ED visits involving acute and chronic alcohol consumption in the United States by age and sex between 2006 and 2014. Data from the Nationwide Emergency Department Sample (NEDS), the largest all-payer ED database in the United States involving 945 hospitals in 33 states and Washington, DC, were analyzed to assess changes in prevalence and rates of ED visits involving acute and chronic alcohol consumption by age and sex over time among persons aged ≥12 between 2006 and 2014. Between 2006 and 2014, the number of ED visits involving alcohol consumption increased 61.6%, from 3,080,214 to 4,976,136. The rate increased 47% from 1,223 to 1,802 per 100,000 population and the total cost of such visits increased 272% from $4.1 billion to $15.3 billion. The number of acute alcohol-related ED visits increased 51.5% from 1,801,006 to 2,728,313 and the rate increased 40% from 720.9 to 1,009.6 per 100,000 population. The number chronic alcohol-related visits increased 75.7% from 1,279,208 to 2,247,823 and the rate increased 57.9% from 502.2 to 792.9 per 100,000. The annual percentage change in rates of all alcohol-related ED visits was larger for females than for males (5.3% vs. 4.0%). Other drug involvement increased the likelihood of admission for inpatient treatment. Alcohol consumption contributed to an increasing number of ED visits in the United States between 2006 and 2014, especially among females. Increased utilization of evidence-based interventions is needed.

Oropharyngeal squamous cell carcinoma incidence and mortality trends in the United States, 1973-2013.

To analyze oropharyngeal squamous cell carcinoma incidence and mortality trends in the United States for the years 1973 through 2013. Cross-sectional study using a large population-based cancer database. Data on incidence and mortality rates were extracted from the Surveillance, Epidemiology, and End Results (SEER) 9 Database. Annual percentage change in rates was calculated using Joinpoint regression analysis (National Cancer Institute, Bethesda, MD). Incidence rates increased (annual percent change [APC]; 1.52, 95% confidence interval [CI] 0.17 to 2.88) from 1973 to 1983, remained stable (APC -0.52, 95% CI -1.30 to 0.26) from 1983 to 1997, and increased (APC 1.32, 95% CI 0.83 to 1.81) from 1997 to 2013. Overall, incidence rates increased for males (APC 0.73, 95% CI 0.22 to 1.25) but not females (APC -0.77, 95% CI -0.68 to 0.82). Incidence rates increased in the white population (APC 0.79, 95% CI 0.33 to 1.25) but decreased in the black population (APC -0.72, 95% CI -1.41 to -0.02). The incidence rates increased for tongue-base tumors (APC 1.17, 95% CI 0.42 to 1.92) and tonsil tumors (APC 0.47, 95% CI 1.10 to 4.96) but decreased for other sites. Incidence-based mortality decreased (APC -0.78, 95% CI -1.13 to -0.42) from 1993 to 2013. Oropharyngeal squamous cell carcinoma incidence rates increased in a nonlinear fashion from 1973 to 2013, whereas mortality rates declined. This, along with variation in trends by demographic and tumor factors, suggest that human papilloma virus is the main driver of the recent rise in incidence. 2b. Laryngoscope, 128:1582-1588, 2018.

Comparison of annual percentage change in breast cancer incidence rate between Taiwan and the United States-A smoothed Lexis diagram approach.

Recent studies compared the age effects and birth cohort effects on female invasive breast cancer (FIBC) incidence in Asian populations with those in the US white population. They were based on age–period–cohort model extrapolation and estimated annual percentage change (EAPC) in the age‐standardized incidence rates (ASR). It is of interest to examine these results based on cohort‐specific annual percentage change in rate (APCR) by age and without age–period–cohort model extrapolation. FIBC data (1991–2010) were obtained from the Taiwan Cancer Registry and the U.S. SEER 9 registries. APCR based on smoothed Lexis diagrams were constructed to study the age, period, and cohort effects on FIBC incidence. The patterns of age‐specific rates by birth cohort are similar between Taiwan and the US. Given any age‐at‐diagnosis group, cohort‐specific rates increased overtime in Taiwan but not in the US; cohort‐specific APCR by age decreased with birth year in both Taiwan and the US but was always positive and large in Taiwan. Given a diagnosis year, APCR decreased as birth year increased in Taiwan but not in the US. In Taiwan, the proportion of APCR attributable to cohort effect was substantial and that due to case ascertainment was becoming smaller. Although our study shows that incidence rates of FIBC have increased rapidly in Taiwan, thereby confirming previous results, the rate of increase over time is slowing. Continued monitoring of APCR and further investigation of the cause of the APCR decrease in Taiwan are warranted.

Análisis de las tendencias en la mortalidad por enfermedades cerebrovasculares en Andalucía (1980-2014)

IntroductionIn recent decades, mortality rates for cerebrovascular diseases (CVD) have decreased significantly in many countries. This study analyses recent tendencies in CVD mortality rates in Andalusia (1980-2014) to identify any changes in previously observed sex and age trends. Patients and methodsCVD mortality and population data were obtained from Spain's National Statistics Institute database. We calculated age-specific and age-standardised mortality rates using the direct method (European standard population). Joinpoint regression analysis was used to estimate the annual percentage change in rates and identify significant changes in mortality trends. We also estimated rate ratios between Andalusia and Spain. ResultsStandardised rates for both males and females showed 3 periods in joinpoint regression analysis: an initial period of significant decline (1980-1997), a period of rate stabilisation (1997-2003), and another period of significant decline (2003-2014). ConclusionsBetween 1997 and 2003, age-standardised rates stabilised in Andalusia but continued to decrease in Spain as a whole. This increased in the gap between CVD mortality rates in Andalusia and Spain for both sexes and most age groups.

Characteristics, incidence and temporal trends of sepsis in elderly patients undergoing surgery.

Despite increasing rates of surgery in the elderly, there is limited population-based information on sepsis in this age group. This study aimed to characterize the epidemiology and national trends of sepsis among elderly patients undergoing surgery in Spain. This population-based longitudinal study of patients aged 65 years or older, undergoing surgery between 2006 and 2011, used data from the national hospital discharge database. Patients were identified by ICD coding. Primary endpoints were incidence and case-fatality rates of sepsis. Predefined age groups were examined. In-hospital mortality-related factors were assessed by means of exploratory logistic regression. Trends were assessed for annual percentage change in rates using Joinpoint regression analysis. A total of 44 342 episodes of sepsis were identified, representing 1·5 per cent of all 2 871 199 surgical hospital admissions of patients aged 65 years or older. The rates varied with age and sex. The in-hospital case-fatality rate was 43·9 per cent (19 482 patients), and associated with age, co-morbidity and organ dysfunction. Standardized rates of sepsis increased over time, with an annual change of 4·7 (95 per cent c.i. 1·4 to 8·5) per cent, whereas the case-fatality rate declined, with an overall annual change of -3·6 (-4·3 to -2·8) per cent. The decrease in mortality was more limited in patients with organ dysfunction and in the oldest age group. Rates of sepsis are increasing among elderly patients undergoing surgery, whereas in-hospital case fatality, although common, is showing a decreasing trend.

Trends in absolute and relative risk of acute myocardial infarction in people with type 2 diabetes in Scotland: a national retrospective cohort study

BackgroundWhether more rigorous monitoring and evidence-based treatment of type 2 diabetes has led to improvements in cardiovascular outcomes is unclear. We aimed to explore trends in incidence rates of acute myocardial infarction in the Scottish adult population with type 2 diabetes compared with the non-diabetic population. MethodsIncidence rates of acute myocardial infarction (first admissions and deaths in and out of hospital) between Jan 1, 2001, and Dec 31, 2010, for adults aged 35–84 years were derived from Scottish Morbidity Records and linked death records. Diabetes diagnoses were ascertained by linkage to the Scottish diabetes register. Trends were analysed with negative binomial regression adjusted for age and an area-based measure of socioeconomic deprivation, and then expressed as annual percentage change in rates. FindingsOf 118 340 incident acute myocardial infarctions, 15 798 (13%) were in people with type 2 diabetes 1·88 million (4%) of 50·7 million person-years at risk were in people with type 2 diabetes. In men and women with and without type 2 diabetes, incidence of acute myocardial infarction decreased over time. Incidence was higher among people with than without type 2 diabetes, with higher relative risks in women than in men. The mean annual fall in rate of acute myocardial infarction was 3·7% (95% CI 3·2–4·2) and 2·3% (2·0–2·7) in women and men without diabetes, respectively; and 5·6% (4·6–6·7) and 4·4% (3·6–5·2) in women and men with type 2 diabetes. Relative risks for acute myocardial infarction declined for people with type 2 diabetes compared with people without type 2 diabetes from 1·5 (1·4–1·7) to 1·2 (1·1–1·3) for men and 1·8 (1·6–2·1) to 1·5 (1·3–1·6) for women between 2001 and 2010. InterpretationRates of acute myocardial infarction decreased over time in all population groups with more pronounced declines among people with than without type 2 diabetes. Secular trends in risk factors and improved primary and secondary prevention of cardiovascular disease are potential explanations for the observed time trends. FundingData linkage of the Scottish population-based register of people with diagnosed diabetes to national hospital admission and mortality records and data management was funded by the Scottish Government through the Scottish Diabetes Group, which had no role in the writing of the abstract or the decision to submit for publication.

Increases in invasive melanoma in England, 1979–2006, by anatomical site

National melanoma incidence trends with details of anatomical site have not been previously described for England. To describe site-specific trends in cutaneous melanoma for England as a whole during the last three decades. Anonymized data, 1979-2006, were obtained from national cancer registrations of all patients in England up to age 89years with incident primary invasive cutaneous melanomas (n=124055). Sex-specific age-standardized incidence rates and average annual percentage change in rates were calculated for each broad anatomical site. Overall incidence rates of cutaneous melanoma in England, 1979-2006, were 81 and 100 per million, in males and females, respectively. Site-specific rates were consistently highest on the lower limbs in females followed by the trunk in males. Greatest annual increases occurred on the trunk in both sexes over 45years (males 9·9%, females 6·8%), then upper limbs (males 8·7%, females 6·8%). Incidence trends in males relative to females varied little across sites apart from a more rapid rise in head/neck melanomas in males than in females after the 1980s. Invasive melanoma rates continue to rise in England, particularly on the trunk and arms, and in males on the head/neck. The steeper increases in melanoma rates among males are consistent with their greater sun exposure and poorer compliance with sun protection measures than females.

Mid-Life Suicide: An Increasing Problem in U.S. Whites, 1999–2005

The overall suicide rate in the U.S. increased by 6% between 1981 and 1986 and declined by 18% between 1986 and 1999. Detailed descriptions of recent trends in suicide are lacking, especially with regard to the method of suicide. Information is needed on the major changes in rates of suicide in specific population groups in recent years (1999-2005). Mortality data came from the Web-based Injury Statistics Query and Reporting System. Suicide trends during 1981-2005 were analyzed by age, race, gender, and method, with an emphasis on increases between 1999 and 2005. Linear regression was used to examine the significance of trends in suicide mortality. The annual percentage change in rates was employed to measure the linear trend in suicide mortality. The suicide rate increased after 1999, due primarily to an increase in suicide among whites aged 40-64 years, whose rate of completed suicide between 1999 and 2005 rose by 2.7% annually for men and by 3.9% annually for women,with increases of 6.3% and 2.3% for poisoning, 2.8% and 19.3% for hanging/suffocation, and 1.5% and 1.9% for firearms for men and women, respectively. Rates did not increase for other age or racial groups [corrected]. The differential increases by age, race, gender, and method underscore a change in the epidemiology of suicide.Whites aged 40-64 years have recently emerged as a new high-risk group for suicide. Although firearms remain the most common method of suicide, the notable increases in suicide by poisoning in men and hanging/suffocation in women deserve prevention attention [corrected].

Childhood Leukemia Incidence in Britain, 1974–2000: Time Trends and Possible Relation to Influenza Epidemics

Time trends in incidence of disease may cast light on etiology. We investigated time trends in childhood leukemia by using Poisson regression methods to analyze data from the National Registry of Childhood Tumours, a long-standing high-quality registry that covers the whole childhood population of Britain. During 1974-2000, the average annual percentage change in rate (AAC) of childhood acute lymphoblastic leukemia (ALL) in Britain was 0.7% (95% confidence interval [CI] = 0.4 to 1.0). This increase was apparently driven by the "common" subtype (expressing the CD10 antigen) of precursor B-cell ALL, for which the estimated AAC during 1980-1996 was 1.4% (95% CI = 0.8 to 2.0). There was no statistically significant time trend in other subtypes of ALL combined (1980-1996) or in acute myeloid leukemia (1974-2000). Small peaks in incidence of ALL in 1976 and 1990 coincided with years immediately following influenza epidemics. These results are consistent with hypotheses that some childhood leukemia may be triggered by infection occurring close to the time of diagnosis of leukemia, particularly in conditions of low herd immunity, and raise the possibility that contact with influenza shortly before the diagnosis of leukemia may sometimes be involved.

Trends for in situ and Invasive Melanoma in Queensland, Australia, 1982–2002

Queensland, the north-eastern state of Australia, has the highest incidence of melanoma in the world. Control measures started earlier here than probably anywhere else in the world; early detection programmes started in the 1960s and primary prevention in the 1980s. Data from the population-based Queensland Cancer Registry therefore provide an internationally unique data source with which to assess trends for in situ and invasive melanomas and to consider the implications for early detection and primary prevention. We used Poisson regression to estimate the annual percentage change in rates across 21 years of incidence data for in situ and invasive lesions, stratified by age and sex. Joinpoint analyses were used to assess whether there had been a statistically significant change in the trends. In situ melanomas increased by 10.4% (95% CI: 10.1%, 11.1%) per year among males and 8.4% (7.9%, 8.9%) per year among females. The incidence of invasive lesions also increased, but not as quickly; males 2.6% (2.4%, 2.8%), females 1.2% (0.9%, 1.5%). Valid data on thickness was only available for 1991 to 2002 and for this period thin-invasive lesions were increasing faster than thick-invasive lesions (for example, among males: thin 3.8%, thick 2.0%). We found some suggestive evidence of lower proportionate increase for the most recent years for both in-situ and invasive lesions, but this did not achieve statistical significance. Among people younger than 35 years, the incidence of invasive melanoma was stable and there was a suggestion of a birth cohort effect from about 1958. Mortality rates were stable across all ages, and there was a suggestion of decreasing rates among young women, although this did not achieve statistical significance. Age-standardised incidence is continuing to increase and this, in combination with a shift to proportionately more in situ lesions, suggests that the stabilisation of mortality rates is due, in large part, to earlier detection. For primary prevention, after a substantial period of sustained effort in Queensland, there is some suggestive, but not definitive, evidence that progress is being made. Incidence rates are stabilising in those younger than 35 years and the proportionate increase for both in situ and invasive lesions appears to be lower for the most recent period compared with previous periods. However, even taking the most favourable view of these trends, primary prevention is unlikely to lead to decreases in the overall incidence rate of melanoma for at least another 20 years. Consequently, the challenge for primary prevention programmes will be to maintain momentum over the long term. If this can be achieved, the eventual public-health benefits are likely to be substantial.

Changes in the Classification of Sudden Unexpected Infant Deaths: United States, 1992–2001

Sudden infant death syndrome (SIDS) makes up the largest component of sudden unexpected infant death in the United States. Since the first recommendations for supine placement of infants to prevent SIDS in 1992, SIDS postneonatal mortality rates declined 55% between 1992 and 2001. The objective of this analysis was to examine changes in postneonatal mortality rates from 1992 to 2001 to determine if the decline in SIDS was due in part to a shift in certification of deaths from SIDS to other causes of sudden unexpected infant death. In addition, the analysis reviews the change in mortality rates attributed to the broad category of sudden unexpected infant death in the United States since 1950. US mortality data were used. The International Classification of Diseases (ICD) chapters "Symptoms, Signs, and Ill-Defined Conditions" and "External Causes of Injury" were considered to contain all causes of sudden unexpected infant death. The following specific ICD (ninth and tenth revisions) underlying-cause-of-death categories were examined: "SIDS," "other unknown and unspecified causes," "suffocation in bed," "suffocation-other," "aspiration," "homicide," and "injury by undetermined intent." The average annual percentage change in rates was determined by Poisson regression. An analysis was performed that adjusted mortality rates for changes in classification between ICD revisions. The all-cause postneonatal mortality rate declined 27% and the postneonatal SIDS rate declined 55% between 1992 and 2001. However, for the period from 1999 to 2001 there was no significant change in the overall postneonatal mortality rate, whereas the postneonatal SIDS rate declined by 17.4%. Concurrent increases in postneonatal mortality rates for unknown and unspecified causes and suffocation account for 90% of the decrease in the SIDS rate between 1999 and 2001. The failure of the overall postneonatal mortality rate to decline in the face of a declining SIDS rate in 1999-2001 raises the question of whether the falling SIDS rate is a result of changes in certifier practices such that deaths that in previous years might have been certified as SIDS are now certified to other non-SIDS causes. The observation that the increase in the rates of non-SIDS causes of sudden unexpected infant death could account for >90% of the drop in the SIDS rates suggests that a change in classification may be occurring.