People often talk about the “rate” of circumcision but this can confuse two different ideas: incidence and prevalence. Incidence refers to the number of persons in a particular group who are circumcised each year; prevalence means how many in that group are currently circumcised. The prevalence of circumcision for newborn boys is zero, because none is born circumcised, but incidence is about 13% in the first year of life. On the other hand, annual incidence of circumcision for intact men in their 20s is about 0.07%, but prevalence in 2012 was estimated at 26%. Below we provide the most accurate estimates of circumcision incidence and prevalence for Australia available either on the Web or in print.
The vast majority of circumcisions in Australia have always been performed routinely on infants. By routine we mean surgery performed without medical indication. The opposite of routine is therapeutic, which means for the treatment of a disease or to correct an anatomical defect. Routine circumcision reached a peak of more than 80% in the 1950s, with most procedures performed on neonates before the birth discharge from hospital. Incidence has fallen steadily since the 1960s, so that today about 85% of boys start primary school still in possession of their foreskins. Further, only 25% of circumcisions for this age group are now performed in a hospital setting; the rest are done in doctors’ rooms, mainly by profit-oriented GPs rather than qualified surgeons working with anaesthetists in theatre.
The number of circumcisions for boys is the sum of Medicare rebates plus procedures performed on public patients in public hospitals. The latter is an important qualification because public hospitals progressively stopped offering this “elective procedure” from the 1990s, and from November 2007 none did (with very partial exceptions in Queensland and the Northern Territory). This is the main reason many people, looking only at Medicare rebates, have claimed that the “circumcision rate” has been going up, when in fact incidence has been very stable over the past decade and has recently begun a renewed decline.
A reader asks if we can obtain a more recent picture of circumcision incidence that includes a State breakdown. There is at least a 2-year lag for release of the relevant hospital data, which are national only. But happily public hospital circumcisions have been of decreasing importance for preschool boys as elective procedures have been phased out. Since Medicare rebates were claimed for 94% of circumcisions in this age group in 2010, Medicare statistics – which are published at monthly intervals – can provide a more current snapshot of incidence, as well as allowing a State breakdown, with only a small loss of accuracy. In order to obtain a more sensitive measure for comparative purposes we can calculate a true rate: rebates per 1000 person-years in this case. The distinction between rate and risk is subtle but important: rate is what actually happened that year for all boys aged 0-4; risk is a prediction of what would happen for boys born that year were the rate to stay the same over the ensuing 4 years.
There are several points to note about this table. First, to obtain a total risk value comparable to that in Table 1, we must add 1 percentage point (based on 2010 data) to the national Medicare estimate. So the total national risk should be 15% in 2011-12, barring unforeseen changes in public hospital practices (for individual States and Territories the equivalent increments vary in ways that are difficult to measure precisely but fall in the range 0.5-1.5%). Second, Victorian and South Australian public hospitals still offered elective circumcision in 2007-08, so the small rate rises in Medicare rebates for these States largely reflected a move from publicly insured to fee-for-service rather than an increase in the actual number of procedures.
Third, and most important, it is now clear that after more than a decade of stability the incidence of infant circumcision started a renewed decline from 2008 in Queensland and NSW, the States with the highest incidence. This is not surprising given the falling prevalence among first-time fathers (see below). Finally, religious (ritual) circumcision is increasing in importance and now accounts for the majority of procedures in Victoria; as with Europe, being circumcised in Australia is becoming a marker of religious identity, with fewer than 10% of boys circumcised for secular reasons by the time they start school.
Since Australian adults are only circumcised in a full surgical setting (public or private hospital, or private free-standing day surgery), we can ignore Medicare data and just use hospital Procedures data for estimates. However, we cannot use total population to calculate a rate, since only intact men can be circumcised. For this we need to know the circumcision prevalence, which was 58% in 2005 for males aged 15-64.
The table indicates that 96% of the 15-year-olds who were intact in 2005 will not be circumcised by their 65th birthday for any reason, if incidence remains the same. But will it? And what are the main reasons for adults being circumcised, anyway? We can use the Principal Diagnosis fields of the same hospital records to answer these questions for phimosis and routine (i.e. elective) circumcision, which combined constitute the reasons for more than 95% of all adult procedures. Table 4 shows the results for men in their 20s, who have seen the most dramatic decline in circumcision prevalence over the past two decades (see Prevalence below). Three-year averages were calculated to “smooth” any random variations in population estimates or case numbers.
The most striking feature of this table is that as intact men move from being a minority to a large majority in their peer group, they are much less likely to opt for circumcision. This means that the already small risk of adult circumcision (incidence) is actually falling as circumcision prevalence falls.
The primary source for prevalence data is the Australian Studies of Health and Relationships, which has conducted large-scale scientific surveys of sexual health issues since 2001. Stratifying this information by birth year and place provides an excellent picture of the changing circumcision status of the adult population, including a breakdown into its Australian-born and overseas-born components (the latter now constituting 30% of the total male population).
The 2005 intake of this survey confirmed these data and found that prevalence for those born in 1987-89 was 27%, which would indicate that the decline in incidence had started to “flatten out” at that time. It is important for a correct interpretation of this graph to understand that while the measured prevalence for all residents (the red line) born in the 1950s was 70% in 2001-02, it would have been higher in, say, 1960. That’s because net migration depresses total prevalence over time, as long as the blue line (Australian-born) is higher than the green line (overseas-born). Analysis of the latest Census data by country of origin indicates the circumcision rate of recent arrivals is about 15%, which means immigration continues to exert downward pressure on adult circumcision prevalence. Prevalence for Australian-born men closely approximates incidence for each birth year, given the relative rarity of adult circumcision. Another way of looking at the same dataset is to plot the prevalence for an age group over time. Again, it is men in their 20s who are of most interest, since it follows that whatever has happened to them will be the case for men in their 30s ten years later; that is, the circumcision prevalence of men aged 20-29 years in 2002 will closely correspond to that of those aged 30-39 in 2012, since they are largely the same people!
The fact that in 2005, for instance, 64% of these men were intact means that in 2015 about two-thirds of first-time fathers will also be intact, creating a demographic feedback loop that increasingly protects the next generation, since the biggest risk factor for infant circumcision is circumcised fathers. The trend (red line) shows a steady fall over 20 years of 2.1% a year. One important implication is that even with the active discouragement of routine circumcision by most of the medical profession, it still took two decades to effect a reversal of incidence (roughly from 70:30 to 30:70). This makes calls for “boosting” RIC as an alleged prophylaxis for certain adult sexual health issues particularly quixotic, since in addition to the lead time for the measure to be relevant (median ages of 34 and 69 years for HIV and penile cancer, respectively), one has to factor in the two or three decades it would take to reverse infant circumcision incidence from its current low level (assuming that were even possible, never mind desirable).
The final question many people ask about prevalence is: how many living males are currently circumcised? This inevitably involves a little more guess-work than the other calculations offered above, particularly for elderly males (born before WWII), but the last table offers a conservative estimate based on population data for 2011.
Note that even if incidence did not change, total prevalence would continue to fall as older males leave the population, largely intact birth cohorts enter, and younger males age.
© John Cozijn, 2013
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