Martha

The last time I saw Martha was on a blustery November afternoon, when her eighty-year-old emaciated body lay bedridden, wheezing, and curled in the fetal position, a tiny sickly lump of human flesh with wiry unwashed grey hair, eyes squeezed tightly shut, and a wrinkled face contorted in pain or despair or both.  A few days later, she died, and a then second-year medical student was forced to cope with the first real loss in his life.

Martha and I had first met four years earlier when, during a religious period in my life, I responded to a church bulletin asking for volunteers to visit this elderly, widowed German lady who was confined to nursing care and who could not attend worship services.  Nearly every Saturday afternoon thereafter, she and I would meet for an hour of snacks and pleasant conversation, and I grew to know her well.  In the late 1940s, after having lost her entire family to Nazi persecution, she had immigrated to the U.S. as the new bride of a dashing young Air Force captain.  Their marriage was long and happy, and after her husband died, she remained fiercely patriotic, decorating her nursing home bedroom with American flags, pictures of the Statue of Liberty, and “God Bless the USA” plaques.  Her two adult children, unfortunately, had little to do with her aside from managing her finances; and so, my weekly visits served as the key highlights of Martha’s last years of life.

On that chilly autumn day when I sat by her bedside for what would become the final occasion, thin nasal cannulae snaked out from her nostrils and across the grimy, long-unwashed sheets to a bedside oxygen machine whose noisy gurgling disturbed the room’s otherwise funereal silence.  Martha lived in a cheap, disreputable nursing facility; her small, poorly lit, dank apartment reminded me of a dungeon.  She had wrapped herself into her favorite blanket, a tattered fleece quilt with a pattern of little red cardinals hopping along tree branches against a background of forest green leaves.  Her bed had a stout wooden frame surmounted by an even stouter headboard that had built-in shelves and drawers decorated with innumerable USA-themed memorabilia, tiny plastic biblical figurines, and stacks of old greeting cards.  The giant structure engulfed Martha’s frail, dying body, and the mattress reeked of stale urine.  “Martha…it’s me. Martha, can you hear me?” I whispered loudly, cognizant of her poor hearing.  She responded to my greeting by turning a bleary-eyed ashen face to me, muttering something incoherent, and falling immediately back into a stupor.  She died four days later, before my next weekly visit.

For some time after Martha’s death, I felt haunted by our last moment together and how it hadn’t ended in cinematic fashion, with the dying character imparting a brilliant, life-altering message to the captivated audience.  According to popular lore, Martha should have awakened, turned lucid eyes to me one last time, and whispered some deep philosophical advice as her parting words.  Instead, she gave me a vacant, expressionless stare and an unintelligible mumble.  I felt as though she and I had in some way failed because we did not generate the necessary amount of profundity and significance during that final encounter.  This sense of failure threatened to eclipse the many fond memories I held from our preceding four years of friendship.  I kept wondering, was all of our time together meaningless simply because the last moments before death seemed so unsatisfactorily unremarkable?

The answer, I have eventually realized, is no.  Do not overemphasize the importance of “last words.”  Obsessing over a loved one’s departing words simply adds undue stress to an already tense moment.  The surviving kith and kin hover ’round their dying friend or family member and scour their final breaths for meaning, coming away disappointed and distraught if they uncover no timeless, breathtaking, everlasting truths.  Fixation on the perimortem period can cause us to overlook the day-to-day words and experiences of life, believing them to hold less importance than the words spoken on the deathbed.  This thinking is fallacy.  The opportunities for gaining wisdom, the chances for finding meaning and wonder and remembrance, come to us daily in our interactions with others.  Life is simply too rich a soil to bear fruit only on the eve of the harvest; instead, we should search daily for new growth.

I kept waiting for Martha to awaken and impart to me some penetrating, soul-shaking, sagacious insight that would shape evermore the direction of my destiny.  She didn’t.  She had already spoken those words, in the countless afternoons we spent talking with one another; in the shaky, scribbled lines of the letters she constantly mailed to me; and in the laughter we shared over hamburger and onion pizza–her favorite.  Her memory should not be relegated to a single, cold, November day out of the hundreds of beautiful, sun-filled, happy ones we enjoyed.  Her brilliance, her beauty, and her wisdom, they were found in her life, not in her death.

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Going home

Apologies for my radio silence over the past week.  I took a vacation to see my family, friends, and former students back home in the southern Great Plains.  It proved to be an eventful trip.

I return to my childhood home rather infrequently, for several reasons.  The journey spans 1500 miles and 10+ hours of travel from my current abode.  As a resident physician, I have few days off and do not want to spend them crammed into questionably roadworthy buses and inhumanely tiny airplane seats.  But, perhaps the biggest factor for my often extended absences from the windswept prairies of my youth is that I have always had difficulty identifying with the prevailing culture there.  Even as a young kid, I knew I tended towards different sociopolitical leanings than did most of my peers.  Not necessarily better leanings, just different.  As I progressed through college, graduate school, and medical school, I slowly migrated eastward towards cultural centers with which I more closely identified.  Nonetheless, family is family and home is home, and so, away to the heartland of America!

The family is doing well.  My parents are nearing retirement and have begun to focus more on leisure activities, such as repainting various rooms in their house, than on the daily office grind.  They have remained inveterate animal lovers, caring for the family’s aged diabetic cat, a sprightly young kitten, countless stray dogs, a troupe of ducklings, and two donkeys.  My siblings are in school pursuing advanced degrees.  When one returns home only once or twice per year, one must also “make the rounds” on all sorts of extended family members: grandparents, cousins, sketchy uncles recently released from the state pen, etc.  Following a rather demanding itinerary set by my mother, I complete the obligatory luncheons and dinner meetings with these individuals and find that they too are doing well.

As noted in prior posts, I used to be a high school science teacher in a school district adjacent to the one I attended as a youth.  This most recent trip home was timed to coincide with the graduation of a large contingent of my former students.  As I watched them walk across the stage and receive their diplomas, as I spoke with them of their excitement and nervousness about attending college, and as I met with some of the incipient seniors who will graduate next year, I felt an uprising of pride and joy such as a parent must feel when watching their own child graduate.  Truly, teaching is the most rewarding profession I have experienced, and I often wonder if I will one day abandon medicine and return to the classroom.

At the latter end of my vacation, I budgeted a few days’ sojourn on the East Coast to spend some time with my old grad school mentor, who is in his seventies.  I am glad I did so.  He developed a serious bacterial infection requiring hospitalization, and I spent most of the weekend sitting at the bedside in his hospital room.  When he was not wracked by pain or slipping into fitful slumber, we spoke at length about a range of topics: from the mundane to the profound.  He is one of the wisest human beings I have ever known, and though I would have preferred a more comfortable setting, I am grateful for the conversations we shared.  He is recovering nicely from this present illness, but I know one day he will not.  On that day, the world will lose a beacon of intelligence, reasoning, and humor, and I will lose the man who inspired me towards healthy discourse.

Thus went my vacation, after which I now need another vacation.

Major Depressive Disorder

Everyone feels sad at times.  It’s not a disease.
Shit happens.
Get over it.
Have a beer.
Pray.
Be a man.
Grow a pair.
You don’t need Prozac,
You need a backbone.
Get off your duff
And get to work.

A healthy and intelligent son
In a supportive, middle-class, two-parent, two-sibling, Protestant household
In rural Oklahoma,
I knew
Depression is a made-up condition
For liberal West Coast hippies
Who’ve strayed from God’s path
And who have never earned an honest day’s living.

Then I went away to college,
To grad school,
To med school,
And tried to kill myself
By jumping
In front of a city bus.

It’s a serotonin imbalance in the brain.
I can trace the neural pathways for you;
I got an A in neuroscience.
But black textbook arrows through the amygdala don’t tell it:
The stasis that permeates one’s being,
Until your muscles feel sodden
And your thoughts struggle against a palpable, impenetrable grey.

Rise from bed every morning, O Sisyphus.
Fatigue.
Putrefaction.
Resignation.
Despair.
The entropic dissolution of vitality.

And
Even with selective serotonin reuptake inhibitors,
You turn to other remedies:
Coffee, cocaine, mutilation, masturbation,
Writing, reading, running, swimming,
Highway driving at 3 AM, 110 mph, windows down, radio up, headlights off.

Anything
To dispel,
For a fleeting instant,
The lassitude, stillness, and weight
Of this disease
That we all know
Is merely an excuse
For laziness.

Medical School: the curriculum

Patients rely on the knowledge and expertise of their doctors, yet they seem poorly informed regarding the process by which relatively normal human beings develop into the storied creatures known as physicians.  The following paragraphs describe the typical four year voyage through medical school–which, despite the striking similarities, should not be confused with a journey through Dante’s Inferno.

The first two years of medical school require students to learn the basic science concepts underlying clinical medicine.  Subjects necessary to master include anatomy, histology, physiology, caffeine consumption, biochemistry, pathology, pharmacology, prolonged sleep deprivation, behavioral science, neuroscience, immunology, disavowal of all social interactions, microbiology, and random advanced molecular theories related to professors’ research areas but unrelated in any respect to diagnosing and treating illnesses.  To complete this monumental task, students employ a number of time-tested learning strategies: watching prerecorded online lecture videos at home while wearing pajamas and eating Lucky Charms; rewatching said lectures online at Starbucks while wearing sweatpants and eating overpriced pastries; and, re-rewatching aforementioned lectures, on 2x speed, while wearing boxer briefs and softly sobbing one’s self to sleep.  Additional techniques include obtaining contraband copies of prior years’ examinations and shamelessly memorizing the answers; querying professors as to the exact lecture slides that contain likely test items; and largely avoiding any effort tantamount to genuine studying.

At the conclusion of their second year, med students take the USMLE Step 1 Exam, which is a nationally standardized test that involves regurgitating in the span of eight hours the contents of every Powerpoint lecture slide ever observed during the students’ previous two years of coursework.  Though having little relevance to one’s ability to practice clinical medicine, Step 1 scores largely dictate where and into which specialties med students will match for residency training after medical school.  Faced with this stress, most med students prepare for the exam by closeting themselves for 6-12 weeks in a musty garret; studying intently for at least 3 hours per day; cruising Facebook and Insta while pretending to study for another 12-15 hours per day; and foregoing all sunlight, human speech, and vestiges of personal hygiene.  Immediately after completing the Step 1 exam, students invariably feel certain that they failed and elect to drown their sorrows by means of a several-day-long binge of alcohol, psychotropic illicit substances, and/or prior seasons of “House.”

During the third year of school, med students enter into the clinical realm of the hospital, where on a daily basis they face ridicule and condescension from attending physicians, residents, nurses, ancillary personnel, patients, janitorial staff, and reasonably perspicacious neonates.  Typically, med students take at least four hours to collect a history and perform a physical assessment of a patient, receive thirteen seconds to present this information to the resident or attending physician before being interrupted, and then stand by quietly as the patient proceeds to give the resident or attending an entirely different account of his or her symptoms.  This scenario repeats itself across a range of required clinical rotations that include pediatrics (also commonly known as “make funny faces” month), internal medicine (“whatever you do, do it pensively” month), obstetrics/gynecology (“wish I could forget seeing that” month), psychiatry (“you thought your Uncle Chuck was crazy” month), neurology (“finally get to use the reflex hammer” month), family medicine (“refer to a specialist” month), and surgery (Lasciate ogni speranza, voi ch’entrate).

Shortly after third year ends, med students take USMLE Step 2, which has two parts.  Step 2 CS requires the examinee to role-play as a doctor and to treat simulated patients.  Speaking rudimentary pidgin English and correctly identifying where in the body the lungs are located are the only skills necessary to pass the exam.  Step 2 CK evaluates students’ clinical knowledge much as Step 1 assessed their basic science knowledge–except that CK has less impact on residency options and therefore elicits only scant studying efforts from most students, unless the student has a pathological addiction to standardized exams and/or wishes to match into a highly competitive specialty such as neurosurgery.

The fourth and final year of medical school stands as a sort of Elysium.  The grueling, mandatory clinical rotations of third year have come, gone, and left their psychological scars.  Students in the fourth year take electives geared towards their specialty of interest; they rediscover the sky, trees, and their university gym; they engage in “research” months that involve reading one or two review articles and thereafter trying to abstain from any other scholastic activity; and, they apply for residency positions.  For those who do not know, residency begins after graduation from medical school and consists of three to seven years of additional training as a resident, or supervised doctor, in a particular clinical specialty.  In the dead of winter and during the year’s worst possible travel season, students receive interview invitations from residency programs that liked the students’ applications or that are desperate for the cheap labor these students will provide as residents.  Either way, students gladly brave snow and ice storms and spend $3,000-$10,000 on airline tickets, hotel rooms, and other travel expenses to attend the various program interviews.  Throughout the interview season, a mafia-like organization known as the NRMP, which claims to be an independent philanthropic entity but which in truth exercises monopolistic hegemony over med students’ lives, serves as the self-appointed intercessor between students and residency programs.  On a spring day known simply as “Match Day,” the NRMP matches students to their “optimal” residency positions based on a patented computer algorithm that a third-grader could have designed but that nonetheless earned the organization a Nobel Prize.

At last, with four arduous years behind them, $250000 of student loan debt, moderate to severe PTSD, and residency positions assigned per dicta of the NRMP, med students reach graduation.  In addition to congratulation cards from relatives whom they’ve never met but who nonetheless are “proud to have a doc in the family,” graduation provides students the opportunity to take their final licensing exam, USMLE Step 3, which as long as it is passed has absolutely no impact on students’ future careers and for which the maximum level of preparation consists of identifying the correct testing facility on the evening before the exam.  Beyond graduation lies the vast Unknown of residency, non-negative monthly incomes, freedom from grades, and being “a doctor.”  Godspeed.

Medical School: the cast

MED STUDENT

Generally considered a semi-sentient creature ranking just below newts and precocious fungi on the evolutionary tree, the medical student is able to process crude emotions and to withdraw from painful stimuli, but has rarely been observed performing higher-level cognitive functions.  Masochistic at best, and likely suffering from pathological psychosis, the med student chooses to undergo four years of studying 100+ hours per week while suffering routine ridicule from clinical instructors who treat him or her with approximately the same level of respect as one treats the sock lint that accumulates at the tips of one’s shoes.  Med students are easily recognizable by their shuffling, dejected gait; by the patronizingly short, white coats they wear; and by the ease with which they create awkward situations, such as turning red-faced and stuttering during the clinical breast exam or gleefully offering to manually disimpact a 90-year-old constipated elderly man.  Being unlicensed, the med student cannot provide any substantive assistance to the medical team but does serve as a convenient scapegoat for any failings of the US medical system–whether medication errors, missing documentation, rising healthcare costs, the collapse of Medicare, or unpalatable cafeteria food.  In a process that still baffles leading scientists and that should terrify the general public, the med student on the July 1st following his or her graduation from medical school ceases to be a lowly bottom feeder and metamorphoses into a resident physician who is expected to knowledgeably manage patients.


RESIDENT

The resident.  A med student in heart; a doctor in theory; a peon in reality.  Residents are the curious hybrids of the clinical world.  They have graduated from medical school and, having earned a medical degree, enjoy the esteemed title of “Doctor,” without any of the privileges: they cannot yet practice medicine independently, they don’t have vacation homes in Monaco, and they don’t drive vintage German automobiles.  Instead, they labor at the hospital under the auspices of attending physicians (see below) in a sort of medieval apprenticeship called “residency,” in which they obtain further medical training in a specific specialty such as emergency medicine or dermatology or orthopedics.  The length of this purgatorial residency varies from three years for primary care fields such as pediatrics to seven years for surgical disciplines such as neurosurgery.  The cushy schedule during residency involves a mere 80-100 hours of work per week.  The resident typically arrives at the hospital at the hearty hour of 3 or 4 AM, visits all of the patients on his or her attending’s list, and then writes notes and places orders for each patient–knowing that the well-rested attending will arrive after a morning tennis match around 11 AM and will berate the resident’s medical decisions while issuing directives that exactly match the resident’s original orders.  The resident then remains at the hospital until 8 or 9 PM to complete the day’s activities and to polish the attending’s golf clubs for tomorrow’s early morning tee time.  Residents are easily spotted as the sleep-deprived zombies in wrinkled scrubs and dingy white lab coats running frenetically around the hospital and answering a constant stream of ringing pagers strapped to their waists.  Raking in an average gross salary of ~$50000, they enjoy a competitive hourly wage of just over $10/hr, an ample return on their investment of 8+ years of higher education and only slightly less than they could make stocking shelves at the local department store or selling their nonvital organs on Craigslist.

 


ATTENDING

The word “attending” operates in everyday speech largely as a participle or gerund (e.g., “Attending church was a Sunday morning tradition…”), but in medicine, it serves as a noun for the doctor in charge of the medical team caring for a patient.  It translates roughly as “Boss Man,” “Divine Being,” or “Your Majesty.”  Technically, the word is only the first half of the phrase “attending physician,” but the full title is rarely necessary; the mere utterance of “attending” generates immediate genuflection–if not prostration–on the parts of all sentient beings in the vicinity.  Having usually studied alongside, and perhaps even tutored, lesser healers such as Hippocrates and Jesus, the attending possesses unassailable authority.  He or she dictates the diagnosis and therapy for each patient under the team’s care and makes certain to criticize, refute, and ridicule any and all aspects of the team’s clinical decision-making.  It is customary for God to seek the attending’s permission prior to intervening in the outcome of any given patient.  For mortal humans, receipt of no fewer than twenty-six Nobel prizes is required before one may speak directly to an attending.  Residents and medical students must not meet the attending’s gaze, and students in particular must take caution not to step within the attending’s shadow, lest they risk immediate corporeal combustion for transgressing the sanctified boundaries of Holiness.  Attendings earn prodigious salaries, take solemn oaths to drive only Porsche and Audi vehicles, and live in resplendent luxury while their resident underlings work 12x harder than they do but can scarcely afford the crumbs of the imported French brioche that the attending has for breakfast every morning.  Lastly, attendings do not die; they answer Death’s page, at their own leisure.

 

Villanelle for Cody

What future lies in eyes of tarnished bronze?
Beneath cruel blows, young boy’s shy gaze burns bright.
Comprising hate or hope, keen glint there dawns.

His father’s fists the sole paternal bonds
Defined in child’s experiential sight.
What future lies in eyes of tarnished bronze?

The monster drinks and strikes and then absconds;
Precocious son bleeds, weeping through the night.
Comprising hate or hope, keen glint there dawns.

Alone, afraid, as precipice dark yawns,
The lad considers life: where to, what’s right,
What future lies in eyes of tarnished bronze?

Perpetuate his father’s sin, mere pawns
To Evil’s might? Or flee and seek Love’s height?
Comprising hate or hope, keen glint there dawns.

Outside the clinic, breeze across the lawns,
As he, my patient, lets his tears alight.
What future lies in eyes of tarnished bronze?
Comprising hate or hope, keen glint there dawns.

Why Do People Die?

The question seems straightforward: why do people die?  Answering it is surprisingly difficult.  One could take the biochemistry perspective and explore the molecular disturbances–such as DNA mutations–that cause individual cells to stop functioning.  Or, from the physiology perspective, one could describe the organ system perturbations–such as shock from blood loss–that cause a human being to cease having independent brain and/or heart activity.  Lastly, from a public health perspective, one could discuss the various causes of death as categorized by mechanism.  Each of these three perspectives offers a unique insight into what it means to be a human and what it means to die.  The public health vantage is the topic for today: what are the top causes of death around the world?  Let’s take a look.

If one considers broadly all ages, both sexes, and all countries around the world, the top five causes of death for the most recent year on record are the following (1):

TopMortality_world_2015

This list is short and simple and easy to understand, but digging into the details can prove illuminating.  Within the general category of “heart disease,” the largest player by far is ischemic heart disease–namely, heart attacks.  Among all cancers, the leading type is lung cancer, followed by liver cancer, colon cancer, and stomach cancer.  Stroke splits into two forms: hemorrhagic strokes, where a person bleeds into their brain, and ischemic strokes, where a clot abruptly cuts off blood flow to a portion of the brain.  Chronic respiratory disease consists primarily of chronic obstructive pulmonary disease, or COPD, a condition caused almost exclusively by smoking.  Unintentional injuries encompass many different mechanisms, but the most prevalent is motor vehicle crashes (1).  Note that none of the major global causes of death is infectious in nature; in public health terms, they are “noncommunicable” diseases, meaning they are not caused by infection with a microbial organism.  If one were to ask, then, in the most general sense possible, “What is the main reason people die around the world?,” the answer would be noncommunicable heart disease.

The data become more interesting when one begins to examine population subcategories.  For instance, comparing the poorest countries in the world versus the richest, the lists of top causes of death show some striking differences (1):

TopMortality_byincome

Among poorer populations, the noncommunicable diseases seen globally play a smaller role–though, notably, they still feature as prominent causes of death.  In the place of these chronic conditions, we see infectious diseases such as pneumonia and diarrhea.  For citizens of the USA or Western Europe, it’s hard to imagine someone dying of diarrhea; but the fact remains, it ranks as the fifth-leading cause of death in the world’s poorest regions.  In contrast, among the world’s wealthiest populations, as in the overall global list, infectious diseases do not appear anywhere in the top five causes of death, and heart disease and cancer remain the two biggest killers.  The category of neurological disease includes chronic degenerative disorders such as Alzheimer dementia and Parkinson disease, neither of which features prominently in poorer settings.  Thus, stratifying the global population by even a single metric, economic status, begins to reveal much wider variation in disease burden than one might have expected based on the overall world data.

Next, we narrow our focus even more, to a single country.  In the United States, the pattern of disease mortality for all ages and both sexes appears similar to that of wealthy countries in general (2, 3):

TopMortality_USA_2015

Note, though, a few differences.  Neurological disorders fall just outside of the top 5 for the US, with Alzheimer dementia ranking in sixth place (2).  Heart disease remains in first position in the US, whereas it has fallen second to cancer among wealthy countries worldwide.  Despite the US having abundant cardiologists, cardiac catheterization labs, and even entire hospitals devoted to nothing but heart problems, heart disease still kills more Americans than does any other cause.  There are many potential explanations for this observation–to be explored in later blog postings!  The US has managed to push stroke to last place in its top 5, while unintentional injuries–mostly car crashes–figure third in the US list, much higher than they do among wealthy countries at large.  These differences between the US and other wealthy countries highlight that even within groups sharing similar demographics there exists variation in the array of diseases faced.

As a former high school teacher, I believe young people represent the most important subgroup within any population.  They literally represent the future of that country, and their health statuses and skill sets will determine the capabilities of the country in twenty years’ time.  Unapologetically, then, I tend to focus my clinical and public health endeavors on youth.  On that note, we turn now to the mortality burden among US young people.  In the US in 2014, the top causes of death for various young age groups were the following (3):

TopMortality_USAyouth_2014

Immediately, one notices that the causes of death for young people differ from the causes of death for the country’s population as a whole.  Other than pediatric cancers and rare birth defects, the mechanisms that kill youth in America are not chronic conditions like heart disease but are largely preventable, often behavior-related, traumatic etiologies.  Car crashes, suicides, homicides.  These are the things killing our kids; and we can adopt measures to prevent or at least to mitigate these traumatic forms of death.  We can engineer safer cars, pass automotive laws that ban texting-and-driving, design smart guns that prevent unauthorized access, improve inner-city cohesion to counteract gang violence, etc.  The young people in a population warrant special public health attention, not only because of their relative value to society but also because of the unique set of life-threats that afflict them.

One final, related note on youth.  We’ve explored the causes of death for young people in the US, but another question one could ask is: what is the actual risk of death?  For children, ages 5-9, the risk of death is almost zero!  Out of every 100000 kids in America aged 5-9 years, only 11.5 die every year–giving a risk of 0.012%.  This is truly incredible when one steps back and appreciates the significance; we as a society have virtually eliminated the risk of death for an entire portion of the population.  Pretty cool.  Unfortunately, the risk of death starts to climb once a child ages into the preteen and adolescent years (3).  As already noted, youth in these age ranges tend to die not from medical illness but from trauma, much of which is likely related to increased risk-taking behaviors.  This observation is tragic, but also encouraging because it means we can potentially affect the statistics.  If as mentioned earlier we apply engineering, policy, and/or socioeconomic interventions to reduce the mortality impacts of adolescents’ risk-taking tendencies, then perhaps we can lower the teen death rate towards that of younger children–thereby saving thousands of lives for future America.

As we’ve seen, the answer to “why do people die” can vary considerably depending on which population one examines.  Further, the preceding discussion has focused only on causes of death; but short of death, diseases can also cause tremendous harm through injury, which is a topic for future discussion.  For now, we’ve established the primary causes of death around the world and at home in the US, and we can now begin to look at those individual etiologies and at ways to combat them.

References

  1. Global Health Estimates 2015: Deaths by Cause, Age, Sex, by Country and by Region, 2000-2015. Geneva, World Health Organization; 2016.
  2. Xu JQ, et al. Mortality in the United States, 2015. NCHS data brief, no 267. Hyattsville, MD: National Center for Health Statistics. 2016.
  3. Heron M. Deaths: Leading causes for 2014. National Vital Statistics Reports; Vol 65 (5). Hyattsville, MD: National Center for Health Statistics. 2016.