Thuan Q. Thach

Trends in breast cancer incidence in Hong Kong between 1973 and 1999: an age-period-cohort analysis.

Hong Kong has the highest breast cancer incidence in Asia and studying secular changes in its rates may lead to hypotheses regarding disease aetiology and also predictions of future trends for China. We examined statistics from the Hong Kong Cancer Registry based on 26 566 cases of invasive breast cancer from 1973 to 1999. The trends in breast cancer incidence were studied using log-linear longitudinal models. We further analysed the independent effects of chronological age, time period and birth cohort on incidence trends using age-period-cohort modelling. The average annual per cent change of the age-standardised incidence was 3.6% during 1973–1999. Age-period-cohort modelling indicated the incidence development was predominantly a cohort effect, where the rise in relative risk was seemingly linear in successive birth cohorts, showing a 2–3-fold difference when comparing women born in the 1960s with those born around 1900. Our results suggest that direct and indirect consequences of westernisation may have been responsible for most of the observed increase in breast cancer incidence. As China moves towards a more westernised way of life, we can expect an emerging epidemic of breast cancer as Hong Kongs experience has demonstrated.Hong Kong has the highest breast cancer incidence in Asia and studying secular changes in its rates may lead to hypotheses regarding disease aetiology and also predictions of future trends for China. We examined statistics from the Hong Kong Cancer Registry based on 26 566 cases of invasive breast cancer from 1973 to 1999. The trends in breast cancer incidence were studied using log-linear longitudinal models. We further analysed the independent effects of chronological age, time period and birth cohort on incidence trends using age-period-cohort modelling. The average annual per cent change of the age-standardised incidence was 3.6% during 1973–1999. Age-period-cohort modelling indicated the incidence development was predominantly a cohort effect, where the rise in relative risk was seemingly linear in successive birth cohorts, showing a 2–3-fold difference when comparing women born in the 1960s with those born around 1900. Our results suggest that direct and indirect consequences of westernisation may have been responsible for most of the observed increase in breast cancer incidence. As China moves towards a more westernised way of life, we can expect an emerging epidemic of breast cancer as Hong Kongs experience has demonstrated.

Will Screening Mammography in the East Do More Harm than Good

OBJECTIVES We sought to systematically review the evidence for population-based mammography as applied to a Chinese population. METHODS Primary reports for meta-analysis were identified by a search of MEDLINE and the Cochrane Library. Outcome measures included breast cancer-related mortality, the number needed to be screened to prevent 1 death, and the positive predictive value of mammography. RESULTS Pooled relative risk for breast cancer-related death in the screened group was 0.80 (95% confidence interval = 0.71, 0.90). Applied to Hong Kong, this figure translates into a number needed to screen of 1 302 healthy women screened annually for 10 years to prevent 1 death. CONCLUSIONS Evidence is insufficient to justify population-based breast cancer screening by mammography for women in Hong Kong and other Asian populations with low breast cancer prevalence.

Air Pollution: Costs and Paths to a Solution in Hong Kong—Understanding the Connections Among Visibility, Air Pollution, and Health Costs in Pursuit of Accountability, Environmental Justice, and Health Protection

Air quality has deteriorated in Hong Kong over more than 15 yr. As part of a program of public accountability, photographs on Poor and Better visibility days were used as representations of the relationships among visibility, air pollution, adverse health effects, and community costs for health care and lost productivity. Coefficients from time-series models and gazetted costs were used to estimate the health and economic impacts of different levels of pollution. In this population of 6.9 million, air quality improvement from the annual average to the lowest pollutant levels of Better visibility days, comparable to the World Health Organization air quality guidelines, would avoid 1335 deaths, 60,587 hospital bed days, and 6.7 million doctor visits for respiratory complaints each year. Direct costs and productivity losses avoided would be over US

Cigarette smoking as a risk factor for influenza-associated mortality: Evidence from an elderly cohort

240 million a year. The dissemination of these findings led to increased demands for pollution controls from the public and legislators, but denials of the need for urgent action arose from the government. The outcome demonstrates the need for more effective translation of the scientific evidence base into risk communication and public policy.

Age-period-cohort analysis of cervical cancer incidence in Hong Kong from 1972 to 2001 using maximum likelihood and Bayesian methods

Please cite this paper as: Wong et al. (2012) Cigarette smoking as a risk factor for influenza‐associated mortality: evidence from an elderly cohort. Influenza and Other Respiratory Viruses 7(4), 531–539.

Short-term, medium-term, long-term, and lifetime risks of developing and dying of breast carcinoma in a Westernized Chinese Population: Evidence from Hong Kong between 1976 and 2000

Objective: To examine the secular effects of opportunistic screening for cervical cancer in a rich, developed community where most other such populations have long adopted organised screening. Design, setting, and participants: The analysis was based on 15 140 cases of invasive cervical cancer from 1972 to 2001. The effects of chronological age, time period, and birth cohort were decomposed using both maximum likelihood and Bayesian methods. Results: The overall age adjusted incidence decreased from 24.9 in 1972–74 to 9.5 per 100,000 in 1999–2001, in a log-linear fashion, yielding an average annual reduction of 4.0% (p<0.001) during the 30 year period. There were two second order and thus identifiable changes: (1) around the mid-1920s cohort curve representing an age-period interaction masquerading as a cohort change that denotes the first availability of Pap testing during the 1960s concentrated among women in their 40s; (2) a hook around the calendar years 1982–83 when cervical cytology became a standard screening test for pregnant women. Conclusions: Hong Kong’s cervical cancer rates have declined since Pap tests first became available in the 1960s, most probably because of increasing population coverage over time and in successive generations in a haphazard fashion and punctuated by the systematic introduction of routine cytology as part of antenatal care in the 1980s.

Modelling the impact of population-based cytologic screening on cervical cancer incidence and mortality in Hong Kong: An age-period-cohort approach

Estimates of lifetime and shorter‐term risks of developing and dying of breast carcinoma are useful translational statistics for risk communication; however, these statistics are unknown for Chinese women, who account for one‐fifth of the worlds female population. In the current study, the authors examined age‐specific 5‐year, 10‐year, 20‐year, and lifetime risks of breast carcinoma incidence and disease‐related mortality among Hong Kong women.

Transmission Dynamics of the Etiological Agent of SARS in Hong Kong: Impact of Public Health Interventions

Cervical cancer incidence and mortality statistics in Hong Kong during 1972–2001 were examined to estimate the potential number of cancer cases that can be averted and years of life saved after the launch of an organised, population-based cytologic screening recall programme in 2004 with projections to 2016. Incidence rates under the status quo of opportunistic screening were projected by an age–period–cohort model, using maximum likelihood and Bayesian methods. Modelled rates were translated into numbers of cancer cases and deaths using mid-year population figures and age–period-specific mortality to incidence ratios. We applied International Agency for Research on Cancer risk reduction estimates for different screening strategies to these base case figures to estimate the number of incident cancers potentially averted and years of life saved attributable to organised screening incremental to the current status quo. The estimated numbers of cases projected to be preventable by the maximum likelihood (Bayesian) approach from 2002 to 2016 were 4226 (4176), 3778 (3728) and 2334 (2287) with organised screening every 1, 3 and 5 years, compared to haphazard screening currently. Correspondingly, 33 000 (32 800), 29 500 (29 300) and 18 200 (17 900) years of life could potentially be saved.